Breath analysis device

ABSTRACT

A breath analysis device into which a user exhales a breath sample is capable of venting an initial portion of the breath sample from the device, and routing a second portion of the breath sample into a disposable cartridge containing an interactant. The device may include a sensor, such as a pressure sensor, for detecting the initiation of exhalation, and may include a controller that switches a valve during the exhalation process to route a desired portion of the breath sample into the cartridge. After the exhalation process, an LED/photodiode arrangement, or another type of optical sensor, may be used to measure a color change produced by a chemical reaction in the cartridge, to thereby measure a concentration of a ketone or other analyte in the breath sample.

PRIORITY CLAIM

This application is a continuation of U.S. application Ser. No.15/339,870, filed Oct. 31, 2016, which claims the benefit of U.S.Provisional Application Nos. 62/247,778, filed Oct. 29, 2015, and62/396,240, filed Sep. 19, 2016. The disclosures of the aforesaidapplications are hereby incorporated herein by reference.

BACKGROUND Technical Field

The present invention relates to apparatuses, systems, and methods forsensing or measuring chemical components or constituents (e.g.,analytes) in the breath of a patient or “subject,” and preferablyendogenous analytes in breath, and to devices and methods for regulatingthe flow of the breath sample during the pre-measurement capture processand/or during such sensing or measurement.

Description of the Related Art

The importance or benefits of measuring the presence or concentration ofchemical constituents in the body to aid in assessing a patient orsubject's physiological or pathophysiological state is well known in themedical and diagnostic communities. Standard approaches tochemically-based diagnostic screening and analysis typically involveblood tests and urine tests.

Blood tests of course require that blood be drawn. Patients associatethis procedure with pain, a factor that can have adverse implicationsfor patient compliance in home-based assessments. In clinical settings,the need to draw blood typically requires trained personnel to draw theblood, carefully and properly label it, handle it and the like. It istypically necessary to transport the sample to a laboratory, often offsite, for analysis. Given the logistics and economics, the lab analysisusually is carried out in bulk on large numbers of samples, thusrequiring bulk handling and logistics considerations and introducingdelay into the time required to obtain results. It is then typicallynecessary for follow-up analysis by the physician or clinician to assessthe lab results and further communicate with the patient. In large partbecause of these logistics and delays, it is usually necessary for thepatient or subject to return for a follow up visit, thus takingadditional clinical time and causing additional expense.

Urine tests involve similar drawbacks. Such tests can be messy,unsanitary, and introduce issues with respect to labeling, handling andcontamination avoidance. They also usually involve lab analysis, withassociated delays and expense. As with blood, urine tests, it istypically necessary to transport the samples to an off-site laboratoryfor analysis. Given the logistics, the lab analysis usually is carriedout in bulk on large numbers of samples, thus again involving delay andexpense.

There are many instances in which it is desirable to sense the presenceand/or quantity or concentration of an analyte in a gas. “Analyte” asthe term is used herein is used broadly to mean the chemical componentor constituent that is sought to be sensed using devices and methodsaccording to various aspects of the invention. An analyte may be orcomprise an element, compound or other molecule, an ion or molecularfragment, or other substance that may be contained within a fluid. Insome instances, embodiments and methods, there may be more than oneanalyte present, and an objective is to sense multiple analytes. “Gas”as the term is used herein also is used broadly and according to itscommon meaning to include not only pure gas phases but also vapors,non-liquid fluid phases, gaseous colloidal suspensions, solid phaseparticulate matter or liquid phase droplets entrained or suspended ingases or vapors, and the like. “Sense” and “sensing” as the terms areused herein are used broadly to mean detecting the presence of one ormore analytes, or to measure the amount or concentration of the one ormore analytes.

The use of breath as a source of chemical analysis can overcome many ofthese drawbacks. The presence of these analytes in breath and theirassociated correlations with physiological or pathophysiological statesoffer the substantial theoretical or potential benefit of providinginformation about the underlying or correlated physiological orpathophysiological state of the subject, in some cases enabling one toscreen, diagnose and/or treat a patient or subject easily and costeffectively. Breath analysis can avoid painful invasive techniques suchas with blood tests, and messy and cumbersome techniques such as urineanalysis. Moreover, in many applications test results can be obtainedpromptly, e.g., during a single typical patient exam or office visit,and cost effectively.

As is well known in the field of pulmonology, breath, and particularlybreath exhalations, comprise a range of chemical components, oranalytes. An “analyte” is a chemical component or constituent that is acandidate for sensing, detection or measurement. Breath compositionvaries somewhat from subject to subject, and within a given subject,from time to time, depending on such factors as physical condition(e.g., weight, body composition), diet (e.g., general diet, recentintake of food, liquids, etc.), exertion level (e.g., resting metabolicrate versus under stress or exercise), and pathology (e.g., diseasedstate). Approximately 200 to 300 analytes can be found in human breath.

Certain breath analytes have been correlated with specific physiologicalor pathophysiological states. Such correlations are particularly usefulfor “endogenous” analytes (i.e., those that are produced by the body),as opposed to “exogenous” analytes (i.e., those that are present inbreath strictly as a result of inhalation, ingestion or consumption andsubsequent exhalation by the subject). Examples are set forth in Table1.

TABLE 1 Candidate Analyte Illustrative Pathophysiology/Physical StateAcetone Lipid metabolism (e.g., epilepsy management, nutritionalmonitoring, weight loss therapy, early warning of diabeticketoacidosis), environmental monitoring, acetone toxicity, congestiveheart failure, malnutrition, exercise, management of eating disordersEthanol Alcohol toxicity, bacterial growth Acetaldehyde Ammonia Liver orrenal failure, protein metabolism, dialysis monitoring, early detectionof chronic kidney disease, acute kidney disease detection and managementOxygen and Carbon Resting metabolic rate, respiratory quotient, oxygenuptake Dioxide Isoprene Lung injury, cholesterol synthesis, smokingdamage Pentane Lipid peroxidation (breast cancer, transplant rejection),oxidative tissue damage, asthma, smoking damage, chronic obstructivepulmonary disease (“COPD”) Ethane Smoking damage, lipid peroxidation,asthma, COPD Alkanes Lung disease, cancer metabolic markers BenzeneCancer metabolic monitors Carbon-13 H. pylori infection MethanolIngestion, bacterial flora Leukotrienes Present in breath condensate,cancer markers Hydrogen peroxide Present in breath condensateIsoprostane Present in breath condensate, cancer markers PeroxynitritePresent in breath condensate Cytokines Present in breath condensateGlycans Glucose measurement, metabolic anomalies (e.g., collected fromcellular debris) Carbon monoxide Inflammation in airway (asthma,bronchiesctasis), lung disease Chloroform Dichlorobenzene Compromisedpulmonary function Trimethyl amine Uremia Dimethyl amine Uremia Diethylamine Intestinal bacteria Methanethiol Intestinal bacteriaMethylethylketone Lipid metabolism O-toluidine Cancer marker Pentanesulfides Lipid peroxidation Hydrogen sulfide Dental disease, ovulationSulfated hydrocarbon Cirrhosis Cannabis Drug concentration G-HBA Drugtesting Nitric oxide Inflammation, lung disease Propane Proteinoxidation, lung disease Butane Protein oxidation, lung disease OtherKetones (other Lipid metabolism than acetone) Ethyl mercaptane CirrhosisDimethyl sulfide Cirrhosis Dimethyl disulfide Cirrhosis Carbon disulfideSchizophrenia 3-heptanone Propionic acidaemia 7-methyl tridecane Lungcancer Nonane Breast cancer 5-methyl tridecane Breast cancer 3-methylundecane Breast cancer 6-methyl pentadecane Breast cancer 3-methylpropanone Breast cancer 3-methyl nonadecane Breast cancer 4-methyldodecane Breast cancer 2-methyl octane Breast cancer Trichloroethane2-butanone Ethyl benzene Xylene (M, P, O) Styrene TetrachloroetheneToluene Ethylene Hydrogen

The inherent relative advantage of breath analysis over othertechniques, together with the relatively wide array of analytes andanalyte correlations, illustrate that the potential benefits breathanalysis offers are substantial.

Notwithstanding these potential benefits, however, with the exception ofbreath ethanol devices used for law enforcement, there has been apaucity of breath analyzers on the commercial market, particularly inmedically-related applications. This lack of commercialization isattributable in large measure to the relatively substantial technicaland practical challenges associated with the technology. Principal amongthem is the requirement for sensitivity. Analytes of interest,particularly endogenous analytes, often are present in extremely lowconcentrations, e.g., of only parts per million (“ppm”) or parts perbillion (“ppb”). In addition, the requirements for discrimination orselectivity is of critical concern. As noted herein above, breathtypically includes a large number, sometimes hundreds, of chemicalcomponents in a complex matrix. Breath also usually has considerablemoisture content. Chemical sensing regimes conducive for breath ammoniameasurement, for example, are preferably sensitive to 50 ppb in thepresence of 3 to 6% water vapor with 3 to 5% carbon dioxide.Successfully and reliably sensing a particular analyte in such aheterogeneous and chemically-reactive environment presents substantialchallenges.

Most publicly-known breath analysis devices and methods involve using asingle breath, and more specifically a single exhalation, as the breathsample to identify or measure a single analyte. The sample is collectedand analyzed to determine whether the analyte is present, and in somecases, to measure its concentration. The breath analysis systemintroduced by Abbott Laboratories, e.g., in U.S. Pat. Nos. 4,970,172,5,071,769, and 5,174,959, provides an illustrative example. There,Abbott used a single exhalation from a patient to detect the presence ofacetone to obtain information about fat metabolism.

Notwithstanding the potential benefits of breath analysis, particularlyportable breath analysis devices for home or field use, commercialofferings of such devices have been available only recently, and theaccuracy and reliability in such settings have left much room forimprovement. Practical breath analysis devices must operate accuratelyand reliably in the context of their use, e.g., in patient homes,clinics, etc., in varying environments, (temperatures, humidity, etc.),with various types of patients, over the life of the devices.

The use of multiple breaths is substantially lesser known and studied.Published reports generally have been limited to the determination ofthe production rate of carbon dioxide and the consumption rate ofoxygen. This technique was developed due to the presence of these twoanalytes (oxygen and carbon dioxide) in the ambient atmosphere.

These approaches have been limited and relatively deficient, however,for example, in that the breath sample or samples are collected in bulk,so that the analyte of interest is mixed in with other constituents.This often dilutes the analyte and increases the difficulty ofdiscriminating the desired analyte. These approaches also limit theflexibility of the breath analysis to undertake more specialized orcomplex analyses.

Additionally, such approaches are relatively deficient because theinstrumentation used for single breath analysis usually is differentfrom and sometimes inadequate for multiple breath analyte measurement.

Yet another challenge to breath analysis involves the fluid mechanicalproperties of the breath sample as it travels through the measurementdevice.

There is considerable advantage in providing breath analysis devicesthat can accurately and reliably sense or measure breath analytes in aclinical or patient home setting. Thus, there is a need for small orportable, cost effective devices and components.

In many instances, there is a need or it is desirable to make theanalysis for an analyte in the field, or otherwise to make suchassessment without a requirement for expensive and cumbersome supportequipment such as would be available in a hospital, laboratory or testfacility. It is often desirable to do so in some cases with a largelyself-contained device, preferably portable, and often preferably easy touse. It also is necessary or desirable in some instances to have thecapability to sense the analyte in the fluid stream in real time or nearreal time. In addition, and as a general matter, it is highly desirableto accomplish such sensing accurately and reliably.

The background matrix of breath presents numerous challenges to sensingsystems, which necessitate complex processing steps and which furtherpreclude system integration into a form factor suitable for portableusage by layman end-users. For example, breath contains high levels ofhumidity and moisture, which may interfere with the sensor or causecondensation within the portable device, amongst other concerns. Also,the flow rate or pressure of breath as it is collected from a usertypically varies quite considerably. Flow rate variations are known toimpact, often significantly, the response of chemical sensors. Breath,especially when directly collected from a user, is typically at or nearcore body temperature, which may be considerably different than theambient temperature. Additionally, body temperature may vary from userto user or from day to day, even for a single user. Devising a breathanalyzer thus is a non-trivial task, made all the more difficult toextent one tries to design and portable and field-amenable device.

Notably, the measurement of endogenous analytes in breath presentsdifferent challenges and requires different techniques and devices thanthe measurement of exogenous analytes. Endogenous analytes are thosethat are produced by the body, excluding the lumen of thegastrointestinal tract, whereas exogenous analytes are those that arepresent in breath as a result of the outside influence or as a result ofuser consumption. However, many analytes are produced endogenously andcan also be exogenously introduced. For example, ammonia is producedendogenously through the metabolism of amino acids, but can also beintroduced exogenously from the environment such as ammonia-containinghousehold cleaning supplies. The term “endogenous” is used according toits common meaning within the field. Endogenous analytes are produced bynatural or unnatural means within the human body, its tissues or organs,typically excluding the lumen of the gastrointestinal tract.

There are a number of significant challenges to measuring endogenousanalytes in breath. Endogenous analytes typically have significantlylower concentrations in the breath, often on the order of parts permillion (“ppm”), parts per billion (“ppb”), or less. Additionally,measurement of endogenous analytes requires discrimination of theanalyte in a complex matrix of background gases. Instead of typicalatmospheric gas composition (e.g., primarily nitrogen), exhaled breathhas high humidity content and larger carbon dioxide concentration. Thisleads to unique challenges in chemical sensitivity, selectivity andstability. For example, chemistries conducive for breath ammoniameasurement are preferably sensitive to 50 ppb in the presence of 3 to6% water vapor with 3 to 5% carbon dioxide.

Because of the historical difficulty in even detecting endogenous breathanalytes, other challenges have not been extensively investigated.Examples of such challenges include: (a) correlating the analytes tohealth or disease states, (b) measuring these analytes givencharacteristics of human exhalation, e.g., flow rate and expiratorypressure, (c) measuring these analytes sensitively and selectively, and(d) doing all these in a portable, cost effective package that can beimplemented in medical or home settings.

Colorimetric devices are one method for measuring a reaction involving abreath analyte. Colorimetric approaches to endogenous breath analysishave historically been plagued with lengthy response times, andexpensive components. Often such analysis has to be performed in alaboratory. Thus there remains a need for a breath analyzer that canmeasure endogenous breath components present in relatively lowconcentrations, such as acetone, accurately and quickly, without a longwait period for results, in addition to being inexpensive and useable bythe layperson. It is also preferable if the breath analyzer is capableof measuring multiple analytes.

SUMMARY

To address these limitations and advance the art, in accordance withsome embodiments, an apparatus is provided for sensing at least oneendogenous analyte from a breath sample comprising at least onesubstantially contemporaneous breath of a patient. The apparatuscomprises a breath input portion that receives the breath sample, and ananalysis portion in fluid communication with the breath input portion.The analysis portion comprises a sensor. The breath sample is directedby the breath input portion to the analysis portion and to the sensor.The apparatus also comprises a processor operatively coupled to thesensor that: (a) segregates the breath sample into a breath profilecomprising the at least one breath, each breath comprising a pluralityof segments, each of the segments of a given breath corresponding to ananatomical region of the patient that is non-identical to the anatomicalregions for others of the segments, (b) selects at least one but lessthan all of the breath profile segments of each of the breaths of thebreath profile to thereby select at least one but less than all of thecorresponding anatomical regions, (c) analyzes the selected at least onebreath profile segments for the at least one endogenous analyte toobtain information about the analyte, and (d) generates a signalrepresentative of the information.

In a related but independent embodiment, a method is provided forsensing at least one endogenous analyte from a breath sample comprisingat least one substantially contemporaneous breath of a patient, themethod comprises providing an apparatus that comprises a breath inputportion and an analysis portion, inputting the breath sample into thebreath input portion and directing the breath sample to the analysisportion, and using the apparatus to segregate the breath sample into abreath profile comprising the at least one breaths. Each of the at leastone breaths comprises a plurality of segments, and each of the segmentsof a given breath corresponds to an anatomical region of the patientthat is non-identical to the anatomical regions for others of thesegments. The method also comprises using the apparatus to select atleast one but less than all of the breath profile segments of each ofthe breaths of the breath profile to thereby select at least one butless than all of the corresponding anatomical regions, analyzing theselected at least one breath profile segments for the at least oneendogenous analyte to obtain information about the analyte, andgenerating a signal in the apparatus representative of the information.

To address these limitations and advance the art, a breath flowregulation device is provided that separates the breath sample into ananalytical portion (e.g., the portion of interest and with which theanalyte measurement will be made) and a residual portion (e.g., portionsof the breath sample other than the analytical portion. This separationcan be achieved using a breath flow regulation device, used inconjunction with a breath analysis device, e.g., as a separate butcooperative apparatus or as an integrated part of the breath analysisdevice. The flow regulation device divides the breath sample intorespective analytical and residual portions and, directly or indirectly,is used to provide the analytical portion to the breath analysis device,where the analytical portion is analyzed to sense the presence of orprovide quantitative information (e.g., the concentration) of theanalyte or analytes in that portion of the breath sample.

In some embodiments, the breath flow regulation device comprises a flowchannel for receiving the breath sample from the user. The flow channelcomprises a first flow path and a second flow path separate from thefirst flow path. The regulation device also comprises a valve in fluidcommunication with the flow channel that directs an analytical portionof the breath sample into the second flow path and diverts a residualportion of the breath sample into the first flow segment. The breathanalysis device receives the analytical portion of the breath sample,directly or indirectly, from the second flow path and senses theanalyte.

In some embodiments, a breath analysis device into which a user exhalesa breath sample is capable of venting an initial portion of the breathsample from the device, and routing a second portion of the breathsample into a disposable cartridge containing an interactant. The devicemay include a sensor, such as a pressure sensor, for detecting theinitiation of exhalation, and may include a controller that switches avalve during the exhalation process to route a desired portion of thebreath sample into the cartridge. After the exhalation process, anLED/photodiode arrangement, or another type of optical sensor, may beused to measure a color change produced by a chemical reaction in thecartridge, to thereby measure a concentration of a ketone or otheranalyte in the breath sample.

Multiple other embodiments are disclosed. They include, for example, adevice that comprises a moveable piston to regulate the flow path, and adevice that comprises a ball valve for flow regulation. Related methodsalso are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are depicted in the accompanying drawings forillustrative purposes, and should in no way be interpreted as limitingthe scope of the inventions, in which like reference characters denotecorresponding features consistently throughout similar embodiments.

FIG. 1 is a breath analysis device that comprises feedback to the userregarding compliance with a breath profile.

FIG. 2 is an embodiment of a breath analysis device.

FIG. 3 is a flow chart demonstrating a method for operating a breathanalysis device using multiple breath profiles.

FIG. 4 shows a depiction of an exhalation as a function of time.

FIG. 5 shows the lung space of a representative patient.

FIG. 6 is an example of a breath profile.

FIG. 7 is another example of a breath profile.

FIG. 8 is another example of a breath profile.

FIG. 9 is another example of a breath profile.

FIG. 10 is another example of a breath profile, with superimposedsegmentation.

FIG. 11 is another example of a breath profile.

FIGS. 12A and 12B demonstrate two valving systems used for rebreathingand non-rebreathing applications.

FIG. 13 is an example of a valving system used to fractionate exhaledbreath.

FIG. 14 is another example of a valving system used to fractionateexhaled breath.

FIG. 15 is a method for using a complex breath profile.

FIG. 16 is an apparatus that uses breath profiles to analyze analytes inbreath.

FIG. 17 is another apparatus that uses breath profiles to analyzeanalytes in breath.

FIG. 18 is another apparatus that uses breath profiles to analyzeanalytes in breath.

FIG. 19 is another apparatus that uses breath profiles to analyzeanalytes in breath.

FIG. 20 is a sensor that utilizes nanoparticle principles.

FIG. 21 is a sensor that utilizes nanoparticle principles.

FIG. 22 is an enzymatic sensor that utilizes optical, orelectrochemical, principles.

FIG. 23 is an apparatus for determining production rate.

FIG. 24 is an apparatus for determining production rate.

FIG. 25 is an embodiment of a breath analysis device that utilizesbreath profiles.

FIG. 26 is an example of a valved breath bag.

FIG. 27 shows a side cutaway view of a breath flow regulation deviceaccording to an embodiment of the invention, wherein the device is in aninitial or open position and directs breath flow through a Flow Path 1.

FIG. 28 shows a side cutaway view of the regulation device of FIG. 27 ,wherein the device is in a position that diverts flow from Flow Path 1to a Flow Path 2.

FIG. 29 shows the regulation device of FIGS. 27 and 28 coupled in abreath analysis device with direct breath input from a user.

FIG. 30 shows the regulation device of FIGS. 27 and 28 coupled to abreath bag.

FIG. 31 shows the regulation device and breath bag of FIG. 30 coupled toa breath analysis device.

FIG. 32 shows a side cutaway view of the regulation device of FIGS. 27and 28 in the open position, and with the guides shown in cross section.

FIG. 33 shows a side cutaway view of the regulation device of FIGS. 27and 28 in the position directing flow through Flow Path 2, and with theguides extending upwardly from the regulation device housing, (thearrows showing where the user would press to move the piston back downto the initial position and thus reset the regulation device).

FIG. 34 shows a top or distal view of the regulation device of FIGS. 27and 28 .

FIG. 35 shows a bottom or proximal view of the regulation device ofFIGS. 27 and 28 .

FIG. 36 shows a side cutaway view of a regulation device according to asecond embodiment of the invention, wherein the regulation device is inan initial or open position and directs breath through a Flow Path 1.

FIG. 37 shows a side cutaway view of the regulation device of FIG. 36 ,similar in perspective to FIG. 36 , but in which the piston is in theclosed position.

FIG. 38 shows a side cutaway view of the regulation device of FIG. 36 ,similar in perspective to FIGS. 36 and 37 , in which the piston has beenreturned to its initial or open position by the biasing spring.

FIG. 39 shows a side external view of a regulation device according toanother embodiment of the invention.

FIG. 40 shows a side cutaway view of the regulation device of FIG. 39 .

FIG. 41 shows a top view of the regulation device of FIGS. 39 and 40 .

FIG. 42 shows a bottom view of the regulation device of FIGS. 39-41 .

FIG. 43 shows a side external view of a regulation device according toanother embodiment of the invention that comprises a ball valve.

FIG. 44 shows a side cutaway view of the regulation device of FIG. 43 ,in which the ball valve is in an initial or open position.

FIG. 45 is a side cutaway view of the regulation device of FIGS. 43-44 ,in which the ball valve is in a closed position that directs breath flowinto a Flow Path 2.

FIG. 46 is a cross-sectional cutaway view of the device of FIGS. 43-45taken from the cutaway shown by the dashed line and in the directionindicated by the arrows in FIG. 44 .

FIG. 47 is a top view of the device of FIGS. 43-45 .

FIG. 48 is a perspective cutaway view of a modification of the device ofFIGS. 43-47 , illustrating the flow of the breath sample during an openphase and during a closed phase of operation.

FIG. 49 shows a breath flow regulation device according to still anotherembodiment of the invention.

FIG. 50 is a flow chart of the user-device interaction for oneembodiment of a breath analysis system.

FIGS. 51A-B show an exemplary cartridge design identifying features andvariables that have been optimized for certain applications described inthis disclosure. FIG. 51A shows a first design with a first flow channeldesign. FIG. 51B shows a second design with a second flow channeldesign.

FIG. 52 is a flow chart of the operating steps of one embodiment of abreath analysis system.

FIG. 53 shows an embodiment of a breath analysis device that works inconjunction with the cartridge shown in FIG. 54 .

FIG. 54 , which includes FIGS. 54A and 54B, shows an embodiment of acartridge with a partially packed reactive chamber. FIG. 54A shows aside view of the cartridge with a partially packed reactive chamber.FIG. 54B shows a top view of the cartridge with a partially packedreactive chamber.

FIG. 55 shows certain internal components of the breath analysis deviceshown in FIG. 53 .

FIG. 56 , which includes FIGS. 56A and 56B, shows the two-step insertionof the cartridge shown in FIG. 54 with the device shown in FIG. 55 .FIG. 56A shows a cross-sectional view of the breath analysis device ofFIG. 53 with a hammer pivoted to an initial upward position. FIG. 56Bshows a cross-sectional view of the breath analysis device of FIG. 53with the hammer pivoted to a downward position.

FIG. 57 shows another embodiment of a cartridge that utilizes reactivematerial other than beads.

FIG. 58 shows the oxygen and carbon dioxide pressures as a function ofvolume of expired air.

FIG. 59 shows the partial pressure of respiratory gases as they enterand leave the lungs.

FIG. 60 , which includes FIGS. 60A-60G shows, various views of anothercartridge embodiment that utilizes a clear viewing window that isdetachably coupled to the remainder of the body of the cartridge. Inthis embodiment, a seal is made with two o-rings. The two o-rings pressto channels on each side of the clear insert. FIG. 60A shows aperspective view of a cartridge embodiment that utilizes a clear viewingwindow that is detachably coupled to the remainder of the body of thecartridge. FIG. 60B shows a side view of a cartridge embodiment thatutilizes a clear viewing window that is detachably coupled to theremainder of the body of the cartridge. FIG. 60D is a cross-sectionalcutaway view of the device of FIG. 60C taken from the cutaway shown bythe dashed line D-D. FIG. 60E is a cross-sectional cutaway view of thedevice of FIG. 60C taken from the cutaway shown by the dashed line E-E.FIG. 60G is a cross-sectional cutaway view of the device of FIG. 60Ftaken from the cutaway shown by the dashed line G-G.

FIG. 61 , which includes FIGS. 61A and 61B, shows another cartridgeembodiment that utilizes a concentric design where Flow Path B surroundsFlow Path A. Optionally, but preferably, the cartridge housing isflexible such that when a breath sample is delivered, the housing shapeis altered to accommodate the volume.

FIG. 62 shows a cartridge embodiment with flexible housing, such that a“bending” motion of the cartridge results in the piercing of an ampoule.

FIGS. 63A-63C show an embodiment of a cartridge that utilizes adifferent packing strategy. FIG. 63A shows a cross-sectional view of thecartridge. FIG. 63B is a cross-sectional cutaway view of the device ofFIG. 63A taken from the cutaway shown by the dashed line B-B. FIG. 63Cis a view of the cartridge from the exterior. The breath sample is firstexposed to an optional desiccant, then to an ampoule (which is initiallysealed) and then to a reactive bead chamber. In this embodiment, thecolor change is monitored perpendicular to the flow of the breath sample(instead of parallel to it).

FIGS. 64A-F show the assembly of a miniature reactive chamber that canwork with the cartridge design shown in FIGS. 63A-63C.

FIGS. 65A-C show various embodiments of a breath analysis system.

FIG. 65A shows a mobile device, a mouthpiece loaded with a multiple-usecartridge, and a base unit. FIG. 65B shows an embodiment of a base unit.FIG. 65C shows an embodiment of an integrated mouthpiece

FIGS. 66A-C show various embodiments of cartridges for a breath analysissystem, such as the breath analysis system of FIGS. 65A-C. FIG. 66A isan embodiment of a single-use cartridge. FIG. 66B is an embodiment of amultiple-use cartridge. FIG. 66C shown an exploded view of an embodimentof a multiple-use cartridge.

FIG. 67 shows an embodiment of an integrated mouthpiece mating with amultiple-use cartridge.

FIGS. 68A-B show an embodiment of a base unit of a breath analysissystem mating with various embodiments of a cartridge. FIG. 68A shows anembodiment of a single-use cartridge mating with a base unit. FIG. 68Bshows an embodiment of a multiple-use cartridge mating with a base unit.

FIGS. 69A-D show screen shots of a mobile application that works inconjunction with the breath analysis device or otherwise with ketoneresults generated from the breath analysis device.

FIG. 70 , which includes FIGS. 70A-70B, shows an embodiment of a breathcapture device that communicates with a processor that may be configuredto control a solenoid valve.

FIGS. 71A and 71B show an embodiment of a breath capture device thatoperates using mechanical principles.

FIGS. 72A, 72B, 73A and 73B show various embodiments of a breath capturedevice that involves interaction with the user to switch the flow path.

FIG. 74 shows a block diagram of an embodiment of breath capture device.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference will now be made in detail to the embodiments and methodsdescribed herein below and as illustrated in the accompanying drawings,in which like reference characters designate like or corresponding partsthroughout the drawings. It should be noted, however, that the inventionin its broader aspects is not limited to the specific details,representative devices and methods, and illustrative examples shown anddescribed in this section in connection with the preferred embodimentsand methods. The invention according to its various aspects isparticularly pointed out and distinctly claimed in the attached claimsread in view of this specification, and appropriate equivalents.

An embodiment of an apparatus (4) for sensing an analyte from a breathsample is shown in FIG. 1 , which illustrates the functional componentsof apparatus (4). In this embodiment, apparatus (4) is a portable devicesuitable for field use, or in the home of a patient or subject, and thusis not confined to use in a laboratory setting. Apparatus (4) comprisesa housing, with a breath input portion in the form of a mouthpieceextending from an end of the housing. The breath input portion accordingto this and other aspects of the invention as described herein is notnecessarily limited to a mouthpiece and may comprise, for example, aconnector for indirect breath sample inputs such as a Tedlar® bagattachment, a hose or pipe connector, or the like. As shown in FIG. 1 ,the breath input portion further comprises an input conduit that extendsthe mouthpiece internally into the housing.

Additionally, because the apparatus may be configured to measure asingle or a plurality of breaths, the breath input may be modifiable. Insome instances, it may be a mouthpiece for a single exhalation, but inother cases, it may be a tube designed for re-breathing. An apparatusthat is capable of using both should be “smart” and capable of modifyingits operating protocols using limited user input.

In some embodiments and methods according to the invention, means areincluded for measuring or controlling certain gas properties orconditions and flow characteristics as breath is inputted into andpasses through the apparatus. Examples of gas properties or conditionsmay comprise pressure, temperature, humidity, viscosity, andconcentration. Examples of flow characteristics comprise mass or volumeflow rate, gas velocity (average or as a function of location, velocityprofiles, etc.), turbulence, pulsation, and pressure differential. Suchparameters facilitate analysis of the phenomenology underlying thebreath analysis, enable more sophisticated designs and analyses, and canprovide feedback to the user if the subject failed to perform themeasurement correctly. They also provide information, signals, triggersand the like for distinguishing between conditions and for switching gasflow, sensor activation and the like, as more fully explained anddescribed herein. Devices or components used to provide thesemeasurements may be essentially any device that can detect or measurethe desired parameter, and may include those known in the correspondingmetrology fields. Examples would include pressure transducers, flowmeters, temperature measurement devices, and the like. In thisembodiment, i.e., apparatus (4), breath sample input flow velocity ismeasured as the subject inhales or exhales into the mouthpiece by abi-directional pneumotachometer disposed in conduit.

Optionally but preferably, apparatus and methods according to theseaspects of the invention comprise at least one fluid conditioner forappropriately conditioning the breath sample as it enters the breathinput and is directed to the analyzing portion. The fluid conditionermay condition the sample, for example, by heating it, cooling it,removing or reducing moisture, restricting the flow rate (e.g., variableor fixed rate of attenuation), converting between laminar and turbulentflow, dampening pressure pulsation, removing or filtering interferentsubstances, and the like, including combinations of these. Asimplemented in the illustrative embodiment shown in FIG. 1 , apparatus(4) comprises a fluid conditioner coupled to the mouthpiece.

Devices and methods according to its various aspects segregate breathsamples into a plurality of segments. Preferably, each of these breathprofile segments correspond to an anatomical region of the patient thatis non-identical to the anatomical regions for others of the segments.

In the embodiment shown in FIG. 2 , apparatus (4) comprises a relativelysimple valving subsystem that selectively switches the breath sampleflow into the analyzing portion. More specifically, a conduit extendsfrom the output of fluid conditioner. A valving device is disposed inthe flow path of the conduit. The valving device in this embodimentcomprises a directional valve that alternatively or selectively directsflow to a first conduit or a second conduit. When the valving device isin a first open position, it directs flow to the first conduit butprevents flow to the second conduit. When in a second open position,valving device directs flow to the second conduit but prevents flow tothe first conduit. The valving device also can assume a closed positionin which flow is prevented to either the first conduit or the secondconduit.

It will be appreciated that considerably more sophisticated and complexsegregating subsystems can be used for physically segregating the breathsample, illustrative examples of which are provided herein below. Inaddition or alternatively, segmentation of the breath sample can beperformed by other means, such as the use of stationary analysis onsegments of the gas flow as the gas passes a given point or region, orsuch segmentation can be achieved or aided using software.Software-based segmentation preferably utilizes real-time sensors orsensors configured to take samples at multiple points during themeasurement process. For example, a real-time oxygen measurement can bemade alongside a trend of accumulated flow. The average oxygen readingwithin the first 25% of lung volume can be compared against the averageoxygen reading in the last 25%.

Apparatus (4) also comprises an analysis portion that in this embodimentcomprises a reaction vessel or cavity 30 fluidically coupled to and influid communication with the first conduit to receive the breath samplefrom the mouthpiece and fluid conditioner when valving device is in thefirst open position. Analysis portion further comprises a sensordisposed at or within reaction vessel so that fluid entering theanalysis portion contacts a second sensor and interacts with itsreactive component or components.

Various sensor designs may be used in conjunction with thisimplementation. Examples include nanoparticle, enzyme-based,thermoelectric, quartz crystal microbalance, optical, colorimetric,metal oxide, semiconductor, magnetoelastic, and gravimetric sensors.Specific yet merely illustrative examples of such sensors include thosedisclosed in U.S. Pat. No. 6,609,068 and U.S. patent application Ser.Nos. 11/656,338, 13/052,963, and 61/593,862, each of which is herebyincorporated herein by express reference as if fully set forth herein.

These sensors may operate continuously, sense the analyte at multiplepoints during a single analysis session, or may simply sense the analyteat one given point in time. For continuous or multiple point analysis,the system preferably would be configured with a “replenishable” orregenerating sensor, or it may require use of multiple disposablecomponents.

An exit or exhaust conduit is disposed at an end of a reaction cavity todirect fluids out of the reaction cavity and externally of the housing.A one-way valve is disposed in the exhaust conduit so that flow ispermitted out of the reaction cavity but not back into it. A bypassconduit is fluidically coupled to the exhaust conduit internally withrespect to the valve so that, when the valving device is in its secondopen position, fluids directed through the conduit are passed to theexhaust conduit and exhausted from the housing.

Apparatus (4) further comprises a processor disposed within the housing.The processor in this embodiment comprises a microprocessor ormicrocontroller appropriately configured and programmed to carry out thefunctions as described herein, in addition to standard housekeeping,testing and other functions known to those in the art. The processor isoperatively coupled to the sensor to receive signals from the sensor asinputs. The processor is operatively coupled to a pneumotachometer toreceive the signal output from the pneumotachometer as an input.

In other embodiments, the processor also is operatively coupled tosegmentation means, e.g., a valving device, so that the processor canboth control the position or state of the device and monitor itsposition. Other examples of segmentation means are a switch that theuser toggles that sets the amount or position of the breath that isanalyzed.

A power supply is disposed in the housing and is operatively coupled tothe processor, the sensor and the valving device to provide necessarypower to those devices.

Apparatus (4) may output the information gleaned from the breathanalysis using any one or combination of output forms or formats. Inthis specific embodiment, apparatus (4) comprises a display disposed onthe exterior of the housing and operatively coupled to the processor.The processor is configured and programmed to output the sensedinformation to the user. This is not, however, limiting. The output alsomay comprise a wired or, more preferably, a wireless data link withanother device, such as a centralized database from which a care giver,such as a physician, family member, watch service or the like canmonitor the output.

The display may and preferably does include feedback for the patient onthe type of breath profile sought for analysis. The feedback may includea trace that describes the flow rate of exhalation and provide user withguidance on how to maintain the optimal flow characteristics.

An implementation of the method according to this aspect of theinvention will now be described with respect to the embodimentidentified herein as apparatus (4). It should be noted and appreciated,however, that the method according to this aspect is not limited to thisspecific apparatus, and may be practiced or implemented with otherhardware configurations. The actual hardware configurations of apparatus(4) also are illustrative, and may be modified in their details tofacilitate such factors or objectives as space use efficiency, thermalcontrols, manufacturability, cost efficiency, and the like. Theelectrical components, for example, may be reconfigured to achieve spaceor power savings, optical components may be substituted, and the like.

In accordance with aspects of the invention, a breath sample is inputtedinto the breath input portion of the apparatus and directed to theanalysis portion. “Breath” as used herein is used according to its broadbut common meaning in the field and includes any gas generated by therespiratory system of the body. For example, breath may be gas in thenasal passages, gas in the bronchial space, gas in the alveolar space,etc. “Gas” as the term is used herein also is used broadly and accordingto its common meaning to include not only pure gas phases but alsovapors, non-liquid fluid phases, gaseous colloidal suspensions, solidphase particulate matter or liquid phase droplets entrained or suspendedin gases or vapors, and the like.

Breath may include a single exhalation or it may include a plurality ofexhalations. Multiple exhalations can take many forms, includingre-breathing and non-rebreathing, which are described herein.

In the analysis portion, the breath sample or a portion thereof isanalyzed to sense one or more analytes. As mentioned herein above, theterm “analyte” is used broadly herein to mean a chemical component orconstituent that is sought to be sensed or measured. An analyte may beor comprise an element, compound or other molecule, an ion or molecularfragment, or other substance that may be contained within a fluid. Insome instances, embodiments and methods, there may be more than oneanalyte present, and an objective is to sense multiple analytes.

In some embodiments and method implementations, the analyte or analytesof interest are endogenous analytes, although this is not necessarilylimiting. The analysis of endogenous analytes in breath presentsdifferent challenges and requires different techniques and devices thanthe measurement of exogenous analytes. As explained herein above,“endogenous” analytes are those that are produced by the body, whereas“exogenous” analytes are those that are present in breath as a strictresult of the outside influence or as a result of user consumption.However, many analytes are produced endogenously and can also beexogenously introduced. For example, ammonia is produced endogenouslythrough the metabolism of amino acids, but can also be introducedexogenously from the environment such as ammonia-containing householdcleaning supplies. Endogenous analytes are produced by natural orunnatural means within the human body, its tissues or organs, typicallyexcluding the lumen of the gastrointestinal tract.

Volatile organic compounds or analytes comprise a particularlyinteresting and useful class of analytes that have significant utilityfor medical diagnostic purposes, and which are well suited for analysisusing various aspects of the invention. The term “volatile organiccompound” or “volatile analyte” is used according to its general meaningwithin the field to include such analytes as small molecules present inhuman breath. While the term “organic” implies carbon containing, we donot intend for the term to be limited in this manner. In other words, weview analytes such as nitric oxide to fall within the definition of avolatile organic compound or a volatile analyte.

Additionally, endogenous analytes for which various aspects of theinvention may be particular well suited and useful include, for example,ammonia and nitric oxide. Ammonia is produced and present in humanbreath as a result of biological processes such as protein metabolism.Nitric oxide is generally present in the upper airway as a result oftissue inflammation and can serve as an indicator of asthmaticconditions and the like.

“Sense” and “sensing” as the terms are used in this document are usedbroadly to mean detecting the presence of one or more analytes, or tomeasure the amount or concentration of the one or more analytes. “Sense”and “analyze” are used interchangeably herein.

“Characterize” as used herein is used according to its broad but commonmeaning within the field and includes obtaining information about theanalyte. For example, characterizing the analyte may involve identifyingthe presence of the analyte, completely or partially determining itschemical makeup (e.g., sequencing a nucleic acid), isolating,determining certain characteristics of the analyte, ascertaining orestimating its concentration, reactivity, and the like. Characteristicsthat may be important include, but are not limited to, size, charge, thepresence of certain functional groups, etc. Size, for instance and incertain implementations, may be determined by gel electrophoresis. Othermanners of identifying an analyte may be used as well.

These aspects of the invention further comprise using the apparatus tosegregate the breath sample into a breath profile comprising the atleast one breath, wherein each of the at least one breaths comprises aplurality of segments, and each of the segments of a given breathcorrespond to an anatomical region of the patient that is non-identicalto the anatomical regions for others of the segments.

A “breath profile” is a specific depiction of breath with certaincharacteristics, such as the duration of the breath, the volume of thebreath used, the volume of breath discarded, the number of breaths, thenumber of exhalations, the number of inhalations, the length of timebetween inhalations and exhalations, etc. A breath profile may be asingle exhalation, but it may also be multiple exhalations separated bya certain period of time. A breath profile may be a natural exhalation,but it may also be a forced expiration or an expiration that iscontrolled (by the patient directly or by a patient assist device) interms of flow rate. Accordingly, there are a number of different breathprofiles that may exist either naturally or because a patient isinstructed to breathe according to the profile.

A few observations regarding respiratory physiology will help tounderscore the significance of different breath profiles and thechallenges associated with characterizing an analyte specific to (e.g.,present in higher concentrations) in one portion or segment of a breathprofile. First, breathing characteristics vary significantly from userto user. A summary of a select few characteristics, relevant to theinstant disclosure, is provided in Table 2, below:

TABLE 1 Characteristics of Breathing Characteristic AbbreviationDefinition Vital Capacity VC Volume of air (L) pushing out of the lungsduring normal breathing. This is typically 80% of an individual's totallung capacity. Residual Volume RV Volume of air (L) remaining within thelungs after a full exhalation. Forced Vital FVC Volume of air (L) thatcan be exhaled with maximum Capacity force and speed, following a normalexpiration. This is typically expelled into a spirometer. ForcedExpiratory FEV Volume of air (L) delivered through a spirometer Volumeduring an FVC exhalation. FEVs are recorded at times t = 0.5, 1.0, 2.0,and 3.0 seconds. FEV-1 (FEV at t = 1 second) normally constitutes 70% ofthe FVC. Forced Expiratory FEF 25-75 Average flow rate of the centerpart of the FEV Flow 25-75% recording. Calculated using time (s) atwhich an individual reaches 25% and 75% of their vital capacity. MaximalVoluntary MVV Average air flow (L/s) recorded as an individualVentilation breaths as deeply and as rapidly as they can for 15 seconds.This is an indicator of respiratory muscle strength and endurance.

Normal values for the above-listed parameters generally vary based onage, gender, and height. Examples of these values can be obtained fromdifferent models, such as the European Respiratory Society 1993 (ERS'93) Model, the Pogar 79 Model, the Third National Health and NutritionExamination Survey (NHANES III) Model, and the Global Lung Quanjer(GLI-2012) Model. Normal values are 80-100% of the predicted values frommodels like NHANES III Model as described above (in other words, thereis some 20% variance within the population).

Variations among users of a breath analysis device may include patientsize, lung capacity, lung strength, etc. These can cause variations inresults even for users with the same concentration of analyte in thelungs or upper airways. The differing properties of the exhalationsprovided by various users affect the fluid mechanical properties of thebreath sample as it travels through the device. Given the sensitivenature of the sensors typically involved, variations in pressure, flowrate and the like can affect results. Larger users or those with greaterlung strength can exhale into a breath analysis device with sufficientflow volume or velocity that the sensor is overwhelmed or otherwise isunable to make an accurate measurement because the device may notcapture the appropriate portion of the breath where detecting theanalyte of interest is optimized.

Further or alternative variation from normal values can occur due tomany factors, including, but not limited to, obstructive or restrictivebreathing. Obstructive breathing may be caused by cystic fibrosis,asthma, bronchiectasis, bronchitis, emphysema or more generally chronicobstructive pulmonary disease (COPD). Restrictive breathing may becaused by heart disease, pregnancy, lung fibrosis, pneumonia,pneumothorax, and pleural effusion. By contrast to the approximately 20%variation in normal values, abnormal values can be substantially lesswith “mild” dysfunction being 60-79% of normal, “moderate” being 40-59%of normal, and “severe” being below 40% of normal.

Additionally, different anatomical regions of the lungs or airway spaceshave been associated with the production or presence of differentgaseous compounds of analytical significance. Of importance is thedistinction between the upper airways (nose, pharynx, trachea, ‘deadspace’ airways) and the alveolar airspace. In general, metabolic gasexchange does not occur in the dead space airways and thus volatilesubstances originating in systemic blood are not sourced from the deadspace airways. Rather, gaseous substances reflecting the localphysiology of the dead space airways themselves (e.g., nitric oxide dueto local inflammation or increased carbon dioxide due to H. pyloriinfection of the gut) will be present in higher concentrations in thedead space airways in comparison to the alveolar airspace. For thesereasons, it is useful to demarcate the anatomical regions of the airwaysin order to link the physiological sources of the various analytes ofinterest to optimum breath profiles for sampling. See FIGS. 4 and 5 . Itis interesting to note that the volume of air inspired routinely by apatient in a state of normal, quiet respiration (“tidal volume”) is onlyslightly more than the volume of the upper airways. Although direct gasexchange with the alveoli is not occurring with each normal breath,diffusion of the gases over the remaining distance takes place rapidly,within less than 1 second (Guyton and Hall, 1996, pg. 484).

Tidal volume is the portion of breath displaced in normal inhalationsand exhalations when no extra effort is applied (e.g., sitting still, atrest, breathing normally without extra depth). Under normalcircumstances, the tidal volume comprises a portion of dead-space, mixedair (including a mixture of dead-space and alveolar air), and alveolarair. The dead-space is air from at least one of the trachea, nasalcavity, and mouth. The mixed air includes some breath sourced from thedeeper regions of the lung, including, for example, the alveoli, but italso contains some breath sourced from the dead-space. The finalsegment, alveolar air, is sourced substantially entirely from the deepersegments of the lungs, including the alveoli—this, third and finalsegment is generally appropriate for analyzing as an alveolar breathsample. Tidal volume varies considerably based on age, sex, and size(e.g., height). As he or she grows, the tidal volume changesconsiderably. Table 3, generated using the ERS Model, shows the tidalvolume as a function of height and age for a representative male andfemale individual. This data may be better understood in view of FIG. 58and its accompanying explanation, presented elsewhere herein.

As can be seen, for example, from Table 3 and FIG. 58 , the averageadult male has a tidal volume measuring about 500 ml and the averageadult female has a tidal volume measuring about 400 ml. The following,simplistic and estimated relationships have been used successfully bysome groups: dead-space=0-150 ml; mixed air=151-300 ml; and alveolarair=301+ ml. However, as males and females have statisticallysignificantly different tidal volumes, percentages may be useful in someapplications. As a broad generalization, for example, the dead-spacesegment of an adult breath can be considered to be about the first20-30% of their tidal volume and the alveolar segment of an adult breathcan be considered to be about the last 30-40% of their tidal volume, butof course this can vary considerably given the various anatomical andother differences described herein.

TABLE 3 Tidal Volume for a Representative Person Over Time Tidal Volume(ml) of Tidal Volume Age Height Female (ml) of Male 5 3′7″ = 43inches~110 cm 157 147 11 4′5″ = 53 inches~135 cm 278 287 15 5′5″ = 65inches~165 cm 424 454 25 5′7″ = 67 inches~170 cm 449 571 31 5′7″ = 67inches~170 cm 439 555 35 5′7″ = 67 inches~170 cm 431 545 41 5′7″ = 67inches~170 cm 421 530 51 5′7″ = 67 inches~170 cm 403 504 61 5′7″ = 67inches~170 cm 385 478 71 5′7″ = 67 inches~170 cm 367 452 81 5′7″ = 67inches~170 cm 379 426

Using the same ERS '93 model, for a given age (31), across differentheights, the vital capacity differs.

TABLE 4 Vital Capacity of Persons Having Various Heights Height FemaleAdult Male Adult 5′1″ = 61 inches~155 cm 3.12 L 3.73 L 5′3″ = 63inches~160 cm 3.34 L 4.02 L 5′7″ = 67 inches~170 cm 3.78 L 4.59 L 5′9″ =69 inches~175 cm 4.00 L 4.88 L 5′11″ = 71 inches~180 cm  4.23 L 5.17 L6′3″ = 75 inches~190 cm 4.67 L 5.75 L

These models are heavily influenced assuming “normal” anatomicalrespiratory characteristics. However, as described above, these valuescan change from individual to individual based on smoking status,pulmonary disease, and illness (e.g., a flu that makes it hard toexhale), among other factors.

Volume that is Vented by the Device

Variability between patients, as explained above, highlights theimportance of adjusting the “vented” or “flushed” gas sample dependingon the individual user. On one hand, it would seem best to just vent the750 mL sample to ensure that an alveolar sample is captured across allpeople. However, this would exclude pediatrics. Moreover, thedifferences between adult men in their late 20s and adult women in their70s is significant: tidal volume of 571 mL v. 367 mL and FVC of 4.70 Lv. 2.85 L (It is important to note that forced vital capacity assumeslittle to no flow resistance, which the user would experience if blowingthrough chemical reagents, a sensor or a valving system).

As such, in one embodiment disclosed herein, a device vents a range ofbetween about 100 mL to 750 mL of exhaled breath in increments of about50 mL. In other embodiments, the device vents a range of between 100 mLto 750 mL of exhaled breath in increments of 100 mL. In yet otherembodiments, which may find highest applicability to adult patients, adevice vents a range of between 300 mL to 750 mL of exhaled breath inincrements of 50 mL or increments of 100 mL. In a pediatric onlyembodiment, a device vents a range of between 50 mL to 100 mL inincrements of either 10 or 25 mL. Young pediatric or neonatal use forapplications such as DKA management or indication of renal failureswould be smaller.

The Trigger for Change by the Device

The trigger to change or “vent” different fractions may be based on oneor more variables other than volume, including, for example flow rateand time or just time as a proxy for volume. As an example, assumingthat about 30% of tidal volume is dead space, an adult male may haveapproximately 150 mL of dead space volume that needs to be exhaledbefore expelling a deep alveolar lung sample (containing about 300 mL).This dead space can be evacuated in about 3 seconds under normalexhalation rates. The device can manipulate the time that a vent isopened for to ensure that only about 3 seconds worth of air (i.e., deadspace) is evacuated before carrying the deep lung sample through to adisposable for analysis. Alternatively, an elderly female may haveapproximately 200 mL of dead space to expel before receiving a deep lungsample, as dead space capacity increases with age. This user may requirethat the dead space be evacuated in about 6 seconds before receiving auseable sample. The device can also manipulate the opening and closingof the vent to allow a longer time for dead space evacuation. Additionalexamples of systems and methods for venting, exhausting, segmenting, orfractionating a breath are provided elsewhere herein.

In some cases, it may be useful to demarcate the anatomical regions ofthe airways in order to link the physiological sources of the variousanalytes of interest to optimum breath profiles for sampling. In FIG. 4, some portions of breath exhalation are labelled. In FIG. 4 , someportions of breath exhalation are labelled. FIG. 4 depicts a plot of anincreasing concentration of substance X as it is exhaled from the lungsover time. As time increases, the region sourcing substance X will alsochange, with the deepest regions sourcing the substance last. In thisexample, very little of substance X, if any, is associated with regionI, corresponding to the upper airways. There is no sharp distinctionbetween these regions as far as gas concentrations are concerned, assignificant mixing takes place between regions due to the fast diffusiontimes of gases. FIG. 4 shows an illustration of possible lung regions.In general, as the lung gases are emptied, the regions will be emptiedin numerical order. By the same token, these regions will also fill innumerical order, and thus the significance extends to both inhalationsas well as exhalations. A given breath profile will consist of aspecification for both.

In a simple case, a specific breath profile might consist of two stages.See FIG. 6 . In this case, the profile is divided into stages A and B.In the figure, the x-axis denotes time and the y-axis shows the pressuredifferential as could be measured with a pneumotachometer. In thisexample (and in the examples which follow), negative pressuredifferentials correspond to inhalations, whereas positive deflectionscorrespond to exhalations. In this example of a specific breath profile,a deep inhalation is immediately followed with a strong exhalation. Thespecification could include further requirements such as “inspire asmuch as is possible and as quickly as is possible” and “exhale as muchas is possible, and as fast as is possible.”

A slightly more complex breath profile might consist of three stages A,B, and C. See FIG. 7 . In this example, a deep inhalation is followed bya rest period of a given duration during which no breathing takes place.A final region shows a strong exhalation.

FIG. 8 shows another possibility. In this example, the breath profile isagain composed of three stages A, B, and C. Stage C, however, differsfrom the previous example in that the exhalation is steady withsub-maximal exertion. A steady, sub-maximal exhalation may be created bya conscientious blower or by the design of the sampling equipment(intentional or otherwise).

The ability to selectively sample the gases from the various regions ofthe airways provides analytical benefit. If all the exhaled gases areexpired into a single collection bag, for instance, then the gasesobtained from lung regions that are not sourcing the analyte of interestwill serve only to dilute the final concentration of the analyte ofinterest in the bag. One approach is to sample only from the region ofinterest in the case of a collection bag.

Sampling from a region of interest can be done with specific breathprofiles. This fractionated sampling can be accomplished byconscientious users or it may be accomplished through instrument design.Conscientious users might breathe the first portion of exhaled air intoa bag (or discard it entirely), and then collect the second portion. Asimple way of doing this would be to breathe for some period of time,and then, after a normal exhalation, wait for 10 seconds and then expirethe remaining air in the lungs. An example of such a profile is shown inFIG. 9 .

FIG. 10 shows an illustrative relationship between expired gasconcentration (in this case carbon dioxide), as it relates to a givenbreathing profile, and lung source region. In this figure, the breathprofile is characterized by three regions A, B, and C. The x-axis istime, the y-axes are the pressure differential as could be measured witha pneumotachometer and the percentage carbon dioxide in the exhaled airas measured with a real-time capnograph. In this figure, a samplingscheme is presented whereby a subject first takes a deep breath,followed by a period of rest and then a steady exhalation. At a pointwhere the carbon dioxide concentration, as measured using the real-timeequipment, crosses a certain threshold, the exhaled air switches itslung sourcing from region I to region II. With continued steadyexhalation, the lung sourcing regions pass through regions III and IV.

Breath profiles need not be limited to single exhalations. In fact,multiple breaths or continual breathing are very useful samplingtechniques. Multiple breaths allow the system and the user's physiologyto come to a steady-state. Measurements are not done on dynamic systemsand thus repeatability is enhanced. Also, by virtue of a steady-statebeing achieved, much more information is revealed about the underlyingphysiology. A continuous breath profile will resemble FIG. 11 . In thisexample, repeated steady breaths are administered. The x-axis is time,the y-axis is the pressure differential as could be measured with apneumotachometer, with the negative deflections indicating inhalationperiods and the positive deflections indicating regions of exhalation.

Breath profiles may intentionally exclude certain behaviors or aspectsof a breath. For instance, a breath profile may be solely oral (e.g.,the patient is wearing a nose clip to prevent nasal “breathing”). Inthis example, a nose clip may be used to prevent gases from leaving thebody or from entering the body, such as in the event that the patientwere in a nail salon and acetone was inhaled (and therefore present inthe body and available for exhalation) due to a high ambientconcentration of nail polish remover.

These aspects of the invention also comprise using the apparatus toselect at least one but less than all of the breath profile segments ofeach of the breaths of the breath profile to thereby select at least onebut less than all of the corresponding anatomical regions.

The process of selecting specific breath profile segments preferably isfocused on obtaining the optimal breath sample, e.g., with the highestconcentration of the analyte or analytes under study and with the lowestinterference or background noise. This can increase the sensitivity andselectivity of the device for the desired analytes. Selection of thespecific breath profile segment or segments also can be used to excludesuch effects and initial breath fluid flow transients or interferences,e.g., at the beginning or end of the breath sample for subjectsbreathing directly into the device.

For applications in which the analyte or analytes of interest are smallmolecules in blood that transmute from the bloodstream into the alveolarspace and which have relatively low diffusion rates, for example, onemay wish to isolate the breath profile segments to those correspondingto the deep alveolar spaces. Even though the analytes may be present insegments corresponding to the upper alveolar spaces and upper airways,the relatively lower concentrations of the analytes in these segmentsmay adversely dilute the analytes and reduce the ability of the sensorto adequately or optimally detect and measure them.

Alternatively, if the analyte of interest resides primarily in the upperairways, for example, such as nitric oxide buildup resulting from upperairway inflammation, one may select a segment or segments correlated toand isolated to the upper airways.

In sensor designs that are sensitive to fluid flow perturbations, highor low flow rates, or the like, one may wish to select breath profilesegments that isolate the sample only to those that have the desiredpressure or flow characteristics. One may, for example, exclude initialand terminal breath profile segments where fluid flow rate is changingand focus on a segment or segments that have essentially steady orlinear flow rates.

These aspects of the invention further comprise analyzing the selectedat least one breath profile segments for the at least one endogenousanalyte to obtain information about the analyte, and generating a signalin the apparatus representative of the information.

Segmenting or fractionating a breath may be accomplished in manydifferent ways, including at least mechanically and electronically(e.g., sensor-based). Mechanical fractionation or segmentation of abreath takes advantage of the pressure (whether positive or negative)generated by the patient during exhalation or inhalation. As describedbelow, by fine tuning mechanical parameters (including, for example,component weight and gas flow path diameters), the pressure generated byone or more breaths can drive a mechanical fractionator. By contrast,sensor-based fractionation or segmentation of a breath relies on using asensor to detect one or more characteristic of the breath (e.g., time,pressure, flow rate, carbon dioxide concentration, oxygen concentration,ammonia concentration, etc.) and actively causing a response by thefractionator (such as movement of a valve or solenoid). Each type ofsegmentation may have certain advantages over the other. For example,mechanical segmentation systems can be very durable whereas electronicor sensor-based segmentation systems can be more prone to componentfailure. Electronic or sensor-based segmentation systems can be verysensitive and allow fractionation into two or more segments (e.g., twosegments, three segments four segments, or even more segments) whereasmechanical segmentation systems can be difficult to tune forfragmentation into more than two segments. Finally, electronic orsensor-based segmentation systems can easily accept and segment multiplebreaths (e.g., can collect various segments of more than one breath)whereas mechanical segmentation systems may require a mechanical or hard“reset” prior a accepting a second breath. Systems and methods for bothtypes of segmentation are discussed below.

Mechanical Segmentation Systems

FIGS. 27 and 28 show an embodiment of a mechanical breath flowregulation device 2010. The regulation device 2010 is shown in these twofigures in side cutaway to illustrate the internal components andoperation. Regulation device 2010 is designed for use with a portablebreath analysis device, for example, such as any of the breath analysisdevices shown and described elsewhere herein and/or in the presentassignee's U.S. patent application Ser. Nos. 14/206,347 and 13/052,963,the specifications of which are hereby incorporated herein as if fullyset forth here. Various sensor designs may be used in breath analysesperformed in conjunction with regulation devices according to theinvention. Examples include nanoparticle, enzyme-based, thermoelectric,quartz crystal microbalance, optical, colorimetric, metal oxide,semiconductor, magnetoelastic, and gravimetric sensors. Regulationdevice 2010 may be used as an integral component of such a breathanalysis device 2012, an illustration of which is shown in FIG. 29 .With continued reference to FIG. 29 , the user directly inputs a breathsample into breath analysis device 2012 by exhaling into a mouthpiece2014 disposed at the distal end of a breath sample input conduit 2016.Regulation device 2010 may be in-line in conduit 2016, which is coupledto the housing of the breath analysis device 2012 at a proximal end ofthe conduit 2016. In some embodiments, a fluid conditioner, for example,a desiccant, is disposed in the mouthpiece 2014 in addition to or as analternative to any regulation device 2010, provided, however, that theflow resistance features of conduit 34 are preserved as describedherein.

Other implementations of regulation device 2010 with respect to thebreath analysis device, however, are within the scope of the invention.With reference to FIGS. 30 and 31 , for example, regulation device 2010may be incorporated into or made detachably coupled to a stand-alonebreath collection apparatus, such as a Tedlar® breath collection bag. Insuch applications, the user first exhales into the breath collection bag2018 while it is separate from the breath collection device, e.g., thebreath collection device 2012 shown in FIG. 30 . The user thendetachably couples the bag 2018 to the breath analysis device 2012 (asshown in FIG. 31 ) so that the breath analysis device 2012 can draw thebreath sample from bag 2018 and perform the analyte analysis on it.Alternatively, the breath analysis device 2012 may comprise a mouthpiece2020, permanently or removably attached to the breath analysis device2012. The user may exhale through or into the mouthpiece 2020 to inflatethe bag 2018 after the bag 2018 has been attached to breath analysisdevice 2012, as shown in FIG. 31 .

There are a number of ways to couple or bond a regulation device (suchas regulation device 2010) to a collection bag (such as bag 2018).Examples include detachable couplers, e.g., a bayonet coupler, and morepermanent bonding, e.g., such as acoustic or sonic welding, adhesive,and the like. The fitment that unites the breath bag to the rigid valvebody may be molded directly into the regulation device body.

With continued reference to FIGS. 27 and 28 , regulation device 2010comprises a hollow and substantially cylindrical housing 2030. Thehousing 2030 of regulation device 10 has an opening 2032 a at itsproximal end 2032 that serves as a flow channel through which the breathsample is inputted. A conduit 2034 is disposed at the opposite, distalend 2036 of housing 2030. In describing this and the various otherembodiments of the invention, the terms “proximal” and “distal” will beused for reference and direction. Proximal is defined as being nearer tothe point(s) at which a breath sample is inputted. By extension, distalis defined as being distant or away from the point(s) at which a breathsample is inputted (i.e., the proximal end). In FIGS. 27 and 28 , forexample, the proximal end is the end closest to the term “BREATH,” i.e.,nearer the bottom of the drawing sheet. In FIGS. 27 and 28 , forexample, the distal direction is the end furthest away from the term“BREATH,” i.e., nearer the top of the drawing sheet. Similarly,references to “top” or “bottom” or “up” or “down” are with respect tothe devices as shown in the drawing figures, even though the devices maybe disposed in directional or geometric configurations other than thoseshown in the drawing figures, (in which case the directional referenceswould change correspondingly).

Conduit 2034 is the path through which the portion of the breath sampleto be analyzed in the breath analysis device 2012 (referred to herein asthe “analytical portion” of the breath sample) flows. In the embodimentshown in FIG. 29 , conduit 2034 is in fluid communication (e.g., directcommunication) with breath analysis device 2012 via conduit 2016. In theembodiment shown in FIG. 30 , conduit 2034 is in fluid communication(e.g., direct communication) with the interior of bag 2018. Conduit 2034may contain (e.g., within its interior) a fluid conditioning material2038, e.g., a desiccant. This partially-filled conduit 2034 provides aresistance to flow relative to an empty conduit. Alternatively, conduit2034 may contain any other material or structure that is configured toprovide a resistance to flow relative to an empty conduit. As will bereadily understood with reference to Poiseuille's equation, as thediameter of a lumen decreases, the resistance to fluid flow through thatlumen increases (assuming all other variable are held constant).Therefore, conduit 2034 may restrict fluid flow (e.g., relative to anempty conduit) merely be having a reduced lumen diameter.

At least one aperture 2040 is disposed at end 2036 of housing 2030 as analternative flow path to conduit 2034. In some embodiments, the at leastone aperture 2040 comprises 1 aperture, 2 apertures, 3 apertures 4apertures, 5 or more apertures, 7 or more apertures 10 or moreapertures, or more than 10 apertures. In some embodiments the at leastone aperture 2040 are disposed exteriorly to the wall of conduit 2034.The apertures 2040 allow a gas or fluid within the interior of housingto pass through them, as will be described more fully herein below.

Regulation device 2010 further comprises a flow switching piston 2042disposed within the interior of housing 2030 and movable or slidablelongitudinally within the housing 2030. Piston 2042 comprises anaperture 2044 through its center. In some embodiments, the aperture 2044is substantially cylindrical and oriented longitudinally through thepiston 2042. However, aperture 2044 may be any other shape and have anyother orientation that produces the fluid flow patterns and necessarypressure profiles for functioning of the regulation device 2010. Forexample, aperture may have a cross-section that is elliptical or ovoid,triangular, square, pentagonal or hexagonal, etc. In the same way, theaperture 2044 may be oriented at an angle to, helically about, and/orlaterally offset from the longitudinal axis of the piston 2042 or theregulation device 2010. A stop flange 2046 is fixedly disposed withinthe interior cavity of housing 2030 adjacent to opening 2032 to stop theproximal movement of piston 2042 at its approach to opening 2032 (i.e.,provide a proximal most location for the piston 2042).

In some embodiments, regulation device 2010 comprises a coupling collar2048 and a seal (e.g., an o-ring 2050) to securely couple the regulationdevice 2010 in airtight fashion to an associated or mating couplingarrangement on a mating conduit, for example, on conduit 2016 in theembodiment of FIG. 29 or bag 2018 of FIG. 30 .

In some embodiments, regulation devices (e.g., mechanical breathsegmenters or fractionators) need not have the capability to be resetfor multiple breath inputs. They may, for example, be designed forsingle use. With respect to regulation device 2010, for example, it isnot necessary to provide a means for returning piston 2042 to itsinitial position at proximal end 2032 of housing 2030. However,resetting the device may be useful in some applications.

Resetting a mechanical fractionator, such as the regulator device 2010shown in FIGS. 27 and 28 , can occur through a number of differentapproaches and configurations, including, for example: gravity resets;spring or biasing resets; mechanical or manual resets; and the like.With reference to FIG. 28 , a gravity reset may function by simplyholding the regulator device 2010 such that its longitudinal axis isapproximately vertical to allow the piston 2042 to slide proximallywithin the regulator device 2010. A gravity reset may be tuned bychanging the mass of the piston 2042, and reducing the friction betweenthe interior surface of the housing 2030 and the exterior surface of thepiston 2042. Of course, if either the mass of the piston 2042 or thefriction between the interior surface of the housing 2030 and theexterior surface of the piston 2042 is changed, it may become necessaryto change the size of the 2044 to fine-tune how easy the piston is movedfrom the proximal end to the distal end of the regulator device 2010. Anembodiment of a spring or biasing reset is described with reference toFIGS. 36-38 . Finally, a mechanical or manual reset may comprise one ormore pins, guide posts, or stanchions extending through a surface of thehousing. An example of a mechanical or manual reset is described withreference to FIGS. 32-33 in which regulation device 2010 comprises atleast a pair of pins, guide posts, or stanchions 2052 disposed on (e.g.,extending from) the distal top surface of piston 2042. Each of theseposts 2052 extends through a corresponding aperture 2054 at housing end2036 adjacent to apertures 2040. In this embodiment, the regulatordevice 2010 may be mechanically reset may be pressing down on one orboth of the guide posts 2054, as shown by the arrows in FIG. 33 . Thisdownward force on posts 2054 urges piston 2042 downward axially withinthe housing interior until the downward movement is stopped by abutmentwith stop flange 2046. Any of a number of other ways of resetting theregulator device may be used.

Regulation device 2010 operates as follows. Prior to receiving a breathsample, piston 2042 is seated in the interior, proximal end of housing2030, e.g., at or adjacent the opening 2032, held by stop flange 2046.Using the embodiment shown in FIG. 29 or FIG. 30 , the user places hisor her mouth at mouthpiece 2014 (FIG. 29 ) or opening 2032 (FIG. 30 )and exhales breath into opening 2032 a in the end 2032 of housing 2030.A portion of the breath passes directly through aperture 2044 in piston2042, but a portion also impinges upon the proximal or bottom surface ofpiston 2042. This creates a relatively higher pressure condition in thecavity at the lower or proximal end of piston 2042 (i.e., the pressureon the proximal end of the piston 2042 is lower than the pressure on thedistal end of the piston), which urges the piston 2042 distally in thehousing 2030, e.g., toward distal end 2036 of the housing 2030.

As the portion of the breath that has passed through piston aperture2044 fills the housing cavity above piston 2042 (e.g., in the housing2030 distal to the piston 2042), it reaches housing distal end 2036. Atthe distal end 2036 of the housing 2030 are two fluid flow paths bywhich a fluid may exit the housing 2030. One flow path (“Flow Path 1”)is from the distal end 2036 of the housing 2030 and through theapertures 2040. The other flow path (“Flow Path 2”) is from the distalend 2036 of the housing 2030 and through conduit 2034.

Flow Path 1 and Flow Path 2 share the total flow as parallel or shuntedflow paths according to principles well known in the field of fluidmechanics. The ratio of their resistances will enable one to predict therespective flow rates through them. Similarly, one may set or adjust therespective resistances of the flow paths to achieve a desired relativeflow through them. The setting of this ratio may be guided by ordetermined from various factors, e.g., such as patient or userdemographics (e.g., age, sex, etc.), by physiological state (e.g.,smoker, non-smoker, hyperventilating, etc.), and so on. In thisillustrative embodiment, the flow resistance in Flow Path 1 isessentially zero and, given the characteristics of the fluidconditioning material 2038 in conduit 2034, the resistance through FlowPath 2 is sufficiently high that most, if not all, of the fluid flowexits the housing 2030 through Flow Path 1. In this example, fluid willcontinue to exit the housing 2030 through Flow Path 1 until piston 2042has traveled the length of housing 2030 and the distal end of the piston2042 contacts distal end 2036 of the housing 2030.

When the piston 2042 reaches the distalmost end of its travel in thehousing 2030, the distal surface of piston 2042 blocks apertures 2040and closes Flow Path 1, which leaves Flow Path 2 as the only remainingexit for the pressurized fluid. Once the apertures 2040 have beenblocked, the fluid flows into proximal housing end 2032, through pistonaperture 2044, into and through and out of conduit 2034 (i.e.,along/through Flow Path 2). As explained above, the conduit 2034 maydeliver the fluid directly to an analyzing device (e.g., breath analysisdevice 2012) or to a collection mechanism (e.g., breath collection bag2018). The portion of a breath sample that passes through conduit 2034(e.g., along Flow Path 2) is referred to herein as the “analyticalportion.” All other portions of the breath sample, most notably theportion that is passed through apertures 40 (e.g., exhausted throughFlow Path 1), is referred to herein as the “residual portion.” Theanalytical portion of a breath sample may be used for sensing ormeasurement of the analyte or analytes in that sample. The residualportion of a breath sample is generally exhausted as waste.

After the breath sample has been forcibly exhaled through a regulationdevice (e.g., regulation device 2010) as described above, if theregulation device is to be re-used the piston (e.g., piston 2042) mustbe repositioned to its initial or open position at the proximal end 2032of housing 2030, as shown in FIG. 27 . This may be accomplished througha number of different means, as discussed above.

A regulation device 2110 according to another embodiment, illustrated inFIGS. 36-38 , will now be described. This embodiment is similar in someaspects to the embodiment shown in FIGS. 27 and 28 and described hereinabove, except that in this embodiment the piston 2042 is automaticallyreturned to its initial (proximal) position when the flow of the breathsample ceases, rather than being manually reset using guide posts 2052.In regulation device 2110, the guide posts 2052 and guide post apertures2054 of regulation device 2010 are omitted. In this embodiment, however,a compression spring 2060 is disposed between the top or distal surfaceof piston 2042 and the lower surface of conduit 2034 at the interior ofthe distal end 2036 of the housing 2030 (such as in a cylindrical insetinto conduit 2034). As shown in FIG. 36 , which illustrates the initialcondition of device 2110 prior to receiving the breath sample, thespring 2060 is extended or biased longitudinally to push or securepiston 2042 at its proximalmost position within housing 2030 and againststop flange 2046.

As shown in FIG. 37 , when a breath sample is exhaled into proximal end2032 of the housing 2030, as described herein above, the flow of thebreath sample applies a pressure- and drag-induced force on the piston2042, which pushes it distally along the longitudinal axis of thehousing 2030 toward the distal end 2036 of the housing 2030. As piston2042 moves/translates under this force, the spring 2060 is compressed,which causes it to oppose further piston movement. The compressionspring 2060 is selected so that the force of the breath flow that urgespiston 2042 distally is greater than the counter-force of thecompression spring 2060. Piston 2042 therefore continues its distalmovement until it contacts the distal end 2036 of the housing 2030 andblocks Flow Path 1. As the piston 2042 block Flow Path 1, fluid flowwill simultaneously shift to Flow Path 2.

As shown in FIG. 38 , the breath input flow into proximal end 2032 ofhousing 2030 attenuates and eventually stops, decreasing and ultimatelyremoving the pressure and drag forces urging piston 2042 distally.Correspondingly, the counterforce of compression spring 2060 urgespiston 2042 proximally. As the pressure and drag forces urging piston2042 distally become less than the counterforce of the compressionspring 2060 urging piston 2042 proximally, the piston 2042 movesproximally (e.g. downwardly) until it is stopped by stop flange 2046.

A regulation device 2210 according to another embodiment will now bedescribed with reference to FIGS. 39-42 . In this embodiment, which issimilar in some aspects to the regulation device 2010 of FIGS. 27-28and/or 2110 of FIGS. 36-38 , the apertures that comprise Flow Path 1(apertures 2040 in devices 2010 and 2110) are of variable size so thatthe resistance presented by Flow Path 1 can be set or adjusted.

In devices 2010 and 2110, the distal end 2036 of the housing 2030 isfixedly disposed at the distal end of housing 2030 and includesapertures 2040 comprising the Flow Path 1. Device 2210 also comprisessuch a distal end 2036 with apertures 2040. However, the device 2210 mayalso comprise a distal housing cap 2236 rotatably disposed over thedistal end 2036. Distal housing cap 2236 comprises apertures 2240 thatcorrespond in number to those of apertures 2040 (i.e., 1 aperture, 2apertures, 3 apertures 4 apertures, 5 or more apertures, 7 or moreapertures 10 or more apertures, or more than 10 apertures), and whichrespectively align with such apertures 2040. As the distal housing cap2236 is rotated, the alignment of apertures 2240 with respect toapertures 2040 is changed, thereby varying (e.g., increasing ordecreasing) the axial cross sectional area of Flow Path 1 (e.g., theresultant combined apertures). This rotatable cap 2236 may comprisecolor coding on its top to facilitate quantification or reproducibilityof the flow through the apertures, and similarly may include numbers ora number scale.

A breath flow regulation device 2310 according to another embodiment ofthe invention will now be described in conjunction with theillustrations of FIGS. 43-48 . This embodiment employs a ball valve toselectively provide for, and then close, Flow Path 1.

An exterior side view of regulation device 2310 is shown in FIG. 43 .Corresponding cross-sectional side views of the device 2310 are shown inFIGS. 44 and 45 . FIG. 44 shows device 2310 at an initial or open stageprior to receiving a breath sample. FIG. 45 shows device 2310 as FlowPath 1 is shut off and flow is directed through Flow Path 2. FIG. 46shows a bottom or proximal exterior view of the device 2310, and FIG. 47shows a top or distal exterior view of the device 2310. FIG. 48 shows aperspective cutaway view of a similar flow regulation device, includingspecifically the internal mechanisms of the ball valve. It comprises aplurality of apertures 2360 a disposed in proximal housing surface 2032that facilitate input of the breath sample into the device in a way thatfacilitates the advancement of the ball.

With continued reference to FIGS. 44-47 , device 2310 comprises ahelical conduit 2360 that starts at aperture 2360 a in the proximal end2032 of the housing 2030, as shown in FIG. 46 , and ends at aperture2360 b in the distal end 2036 of the housing 2030, as shown in FIG. 47 .A ball 2362 that is sized smaller than the cross-sectional dimensions ofthe helical conduit 2360 (so that it can travel through the helicalconduit 2360), but larger than apertures 2360 a and 2360 b (so that itcannot exit the helical conduit 2360 through either of the apertures2360 a and/or 2360 b), is disposed in helical conduit 2360. Thus, FlowPath 1 extends from proximal aperture 2360 a to distal aperture 2360 bvia helical conduit 2360, and Flow Path 2 extends from proximal opening2032 a through conduit 2034. In some embodiments, the ball 2362comprises a light weight plastic such as polypropylene. In otherembodiments, the ball 2362 comprises steel or another suitable material,Device 2310 is designed to be positioned vertically during normaloperation, as shown in FIGS. 43-45 . In this way the slope, length andcross-sectional dimensions of the helical conduit 2360 as well as thedimensions and weight of the ball 2362 may be tailored such that theball 2362 may be pushed up the helical conduit 2360 at a constantvelocity by a constant or linear force. Under initial conditions priorto receiving a breath sample, ball 2362 is held at proximal aperture2360 a by gravity. A viscous material like petroleum jelly or acardboard insert may be used to keep the ball in place prior to use.

When a breath sample is inputted into device 2310 at its proximal endopening 2032 a as generally described herein above with respect to theother embodiments, the flow of the breath sample is restricted in FlowPath 2 by the fluid conditioning material 2038 in conduit 2034, and thusflows in Flow Path 1. The flow overcomes the weight of ball 2362 andpushes it up and through helical conduit 2360. When ball 2362 reachesthe top of helical conduit 2360 at distal aperture 2360 b, the ball 2362lodges in aperture 2360 b and blocks flow through Flow Path 1. When flowis blocked through Flow Path 1, flow is diverted to Flow Path 2,including into, through, and out of conduit 2034 where it may becollected for analysis, such as in a breath analysis device, or forstorage device, such as in a breath collection bag.

Still another embodiment of a mechanical regulation device is shown inFIG. 49 . Much like the device illustrated in FIGS. 27 and 28 , thisdevice comprises a sliding piston-like ring. However, in the regulationdevice shown in FIG. 49 , the conduit 2034 (e.g., a fixed tube overwhich the piston-like ring slides) is disposed in the central, axialportion of the piston. Furthermore, the piston comprises at least onecut-out or slot disposed around its periphery (e.g., a plurality ofslots). As a breath sample is inputted into the device as shown by thearrows, flow resistance in conduit 2034 causes flow to be directedthrough the slots at the periphery of the piston (Flow Path 1), and thepiston is moved axially in the device housing in the direction shown bythe arrows. When the piston contacts the distal end of the housing, itblocks exhaust holes in the distal end of the housing, thereby blockingFlow Path 1 and causing flow to be directed through Flow Path 2 throughthe central conduit 2034. Movement of the piston may be tailored byincreasing the number and or size of the slots. For example, in someembodiments, the piston may include only one slot. In other embodiments,the piston may include 2 slots, three slots, four slots, five slots,five to ten slots ten to fifteen slots, fifteen to twenty slots, morethan twenty slots, or any other number of slots that produces the fluidflow patterns and necessary pressure profiles for functioning of theregulation device.

As will be readily understood, each embodiment of a mechanicalsegmentor/fractionator discussed above may be tailored using principlesof fluid dynamics such that the fractionator (regulator device) capturesan earlier or later, larger or smaller segment of a breath. Assuming areproducible breath, representative variables that can be tailoredinclude: resistance to fluid flow past piston (or ball) (this may bealtered by increasing/reducing the diameter and/or the length of theaperture through the piston); resistance to fluid flow through conduit2034 (this may be altered by increasing/reducing the packing fraction ofthe fluid conditioning material, or increasing/reducing the diameterand/or length of the conduit); and resistance to fluid flow through theapertures in the distal end of the regulator (this may be altered byincreasing/reducing the number and diameter and/or length of theapertures in the distal end of the regulator—much as was described withreference to FIGS. 39-42 ). Each of these variables may be changed so asto change the segment of the breath that is captured.

It is also possible to combine more than one mechanical fractionator toseparately capture one than one segment of a breath. For example: afirst piston device (such as is shown in FIGS. 28 and 28 ) could becombined with a second, potentially concentric, piston device; or apiston device (such as is shown in FIGS. 28 and 28 ) could be combinedwith a ball and helix (as shown in FIGS. 43-47 ). Each stage of such amechanical fractionator could be tailored, as discussed above, so as tocapture different segments of a breath. For example: the first stagecould exhaust a first, early segment of the breath then deliver theremainder of the breath (comprising a first analytical portion and asecond analytical portion) to the second stage; the second stage couldthen split the remainder of the breath into a first analytical portionand a second analytical portion.

While mechanical fractionators may be particularly durable and easy touse, they may suffer from certain user-derived and analyticallimitations. First, mechanical fractionators may require a constantpressure (e.g., a constant exhalation, or at least an exhalationconstantly above a minimum flow rate) to move the device. Young orparticularly weak individuals may have difficulty maintaining such aconstant flow rate, particularly for multi-stage mechanicalfractionators. Second mechanical fractionators may suffer from somedegree pressure bias. That is to say that a user with particularlystrong lungs who is able to exhale with sufficient force to generate acomparatively massive amount of initial pressure may be able to“saturate” the mechanical fractionator and cause it to segmentfalsely—in this case, the mechanical fractionator will segment thebreath too early. By the same token, a user who does not exhale hardenough or exhales for too long a time may experience losses due to fluidleakage which will cause the mechanical fractionator to segmentfalsely—in this case, the mechanical fractional will segment the breathtoo late. Only in a lossless mechanical fractionator (including bothfrictional losses and fluid/pressure leakage/losses) will segmentationbe perfectly reproducible. However, it will be easily understood thatsome variability may be acceptable. Additionally, mechanicalfractionators rely only on flow rates and time and are entirely immuneto other, potentially more accurate, indicia of breath segmentation. Forat least the above-listed reasons, electronic or sensor-basedfragmentation systems and methods, including, but not limited to, thosedescribed below, may be useful.

Electrical or Sensor-Based Segmentation

Electronic or sensor-based fragmentation systems and methods generallydetermine how much breath has passed through any part of the system byusing any of a number of sensors. For example, sensor-basedfragmentation systems may include a timer, a temperature probe, a carbondioxide sensor, or a flow sensor or a combination of any of these. Eachof these sensors outputs a variable that is indicative of one or moreportions of a breath. At least one flow controlling element, e.g., avalve or other device, may be included to responds to the sensoroutputs.

In one embodiment, a sensor-based fragmentation system includes a timesensor (e.g., simple timer, or a clock). After the system detects thestart of the breath input (described elsewhere herein), the system maywait a fixed amount of time before enabling a valve (or other breathdirection system) so as to discard a certain segment breath, e.g., thesystem may discard the entire portion of the breath corresponding to theuser's dead space. The time the device waits may be a fixed amount oftime (such as a preset amount of time), or may be determined through acalibration step. For example, the device may wait 5 seconds beforeenabling the valve, thereby allowing the next 5 seconds of breath toflow through Flow Path A. In some embodiments, a time sensor/timer iscombined with a table of data stored within the device. The table may beany data set indicative of breath characteristics, such as those severaltables presented herein. For example, a tidal volume table having datafor sex, age, and height may be incorporated or used. The device mayallow a user to input their sex, age, and height (or allow anotherperson to input a patient's sex, age and height, e.g., in the case of achild or hospital patient). Then the device can use the input data tolook up and or extrapolate the user's tidal volume. Depending on thebreath segment desired to be captured, the theoretical tidal volume canbe used to identify a theoretical time corresponding to that breathsegment. A processor contained within or associated with the device setsthe time sensor/timer to respond at that calculated theoretical time.Thereby, the device can be customized to any given patient with littlepatient involvement.

In another embodiment, the system may incorporate a flow sensor. Theflow sensor measures the amount of air that has passed through thesystem and activates the valve after a certain volume has passed inorder to capture a certain segment of a breath (e.g., alveolar breath).A flow sensor may be ideally suited to capturing a first segment of abreath, e.g., a first 200 ml, 300 ml, etc. However, capturing othersegments, such as middle or final segments, may present additionalcomplexity for flow-sensor based systems. It will be readily understoodthat a system exploiting a flow sensor to identify and capture varioussegments of a breath can benefit from one or more look up tablescontaining data corresponding to various breathing parameters forvarying segments of the population. As a flow sensor can only measurethe volume of a substance, in this case a fluid, that has passed theflow sensor, particularly valuable variables may include a patient'stotal lung capacity, vital capacity, residual volume, forced vitalcapacity, and forced expiratory volume. A data table may include onlythe data relevant to a pre-determined user. For example, a breathanalysis device issued or prescribed to a 72-inch tall 30 year old malemay have only the data relevant to a 72 inch tall 30 year old male. Adata table may include data for multiple segments of the population,including male and female. Moreover, such data tables may include datafor varying heights, e.g., in one in or one half inch increments (or incentimeter increments) and varying ages, e.g., in one month incrementsor one year increments. By including more data in the look up tables ordata tables, the device may increase its accuracy and applicability tomultiple users. A device with a comprehensive data table may be able toaccept an input from a 75-inch male or from a 61-inch female andidentify that the male has a vital capacity of approximately 5.75 literswhereas the female has a vital capacity of approximately 3.12 liters.Using that information, the device may be able to more accuratelycollect various parts or segments of these user's breaths. This isparticularly so when a later-exhaled breath segment is sought to becollected—if the last ⅓ of the patient's volume is desired, adramatically higher volume of fluid will have to pass for the male thanfor the female.

Data tables rely on statistical average. However, some users may haveaberrant characteristics. For example, it is possible that a givenfemale may have an uncharacteristically high (or low) vital capacity anda given male may have an uncharacteristically low (or high) vitalcapacity. Merely using data tables for these individuals may well resultin false assumptions and miss-collection of breath samples (e.g.,collection of an incorrect or undesired breath segment). Therefore,rather than using data tables to customize a device to a given user, thedevice may be calibrated by/to an individual user so that it can likely(e.g., have a higher likelihood) capture the desired and correct breathsample (e.g., alveolar breath). In some embodiments, the device may becalibrated by sampling a user's exhalations one or more times.

To calibrate a device to a given user using pre-collection exhalation, auser may take a deep breath and exhale for as long as they can one ormore times (e.g., two times, three time, four times, five times, 6times, or even more than 6 times) into the device or cartridge. Thecartridge in this example may be a special cartridge designed forcalibration. During this calibration step the system will learn certaincharacteristics of the user (their vital capacity, residual volume,forced vital capacity, forced expiratory volume, their forced expiratoryflow 25-75%, or their maximal voluntary ventilation, how long they canexhale, how much volume of air they exhale, the changes in flow of theuser's exhalation, the change in pressure when the user exhales, thepresence or absence of certain analytes during an exhalation, etc.). Thedevice may use one or more of these characteristics to determine howmuch breath will pass through the system or to derive the appropriatetime to switch from one flow path (e.g., Flow Path B) to another flowpath (e.g., Flow Path A). Calibration devices such as those describedabove may also be used to train a user.

Calibration may advantageously be used to accurately and reproduciblycollect a deep lung, or alveolar, sample. For example, a user may usecalibrate the collection device to their lung volume or capacity (or anyother breath characteristic) and then use that information to controlthe volume of breath that is vented from the collection device, eitherautomatically or based on user input. The following steps illustrate oneembodiment of a method for such calibration and configuration. First, abreath profiling device (which may be separate form or integral to abreath analysis device) measures the lung capacity, and/or otherexhalation characteristics of the user, as the user exhales into thebreath profiling device. In some embodiments, only one exhalation isrequired for complete calibration. In other embodiments, more than oneexhalation is required for calibration (e.g., 2, 3, 4, 5, or even sixexhalations). After exhaling properly into the breath profiling device,the breath profiling device characterizes the exhalation(s). In someembodiments, the breath profiling device includes the ability andfunctionality to identify and differentiate between proper exhalationscapable of calibrating the device (based on volume, flow rate, or othercharacteristics) and improper exhalations that should be discardedunused for the purposes of calibration). When the breath profilingdevice detects an improper exhalation, it may take any of a number ofactions: it may abort the calibration; it may flag the exhalation asaberrant; or it may assign an aberration index to the exhalation forlater use and/or analysis. The breath profiling device then conveys thecharacteristics, or information derived therefrom, to the breathanalysis device. In some embodiments, the characteristics or informationderived therefrom are conveyed using Bluetooth, Wi-Fi, or any otherappropriate wireless data transfer protocol, or they may be conveyedusing a wired connection. Next, a processor of the breath analysisdevice uses the received information (including at least thecharacteristics or information derived from the exhalations) to controlthe timing with which a valve or other type of flow/exhaust control isactivated during a sample collection exhalation. For example, if themeasured lung capacity/volume is C, the processor may activate the valveonce the user has exhaled X % of C, where X is selected to capture analveolar segment. The breath analysis device may also use the properlycalibrated exhalations (e.g., the stored breath profile informationreceived from the breath profiling device) as a standard for any laterexhalation intended for analysis. For example, the breath analysisdevice may compare an exhalation to the user's stored breath profile todetermine if the exhalation is proper or aberrant. If the exhalation isproper, the breath analysis device may continue with its analysis of theexhalation. Alternatively, if comparison of the exhalation and thestored breath profile (e.g., previous calibration data) identifies anexhalation as abnormal, aberrant, or improper (e.g., if the exhalationcharacteristics do not sufficiently match the user's pre-stored breathprofile), the breath analysis device may abort the test and analysis ofthe exhalation or it may flag the resulting test results (e.g., the testresults derived from the abnormal exhalation) as being aberrational.

Calibration using a breath profiling device may also prove particularlyuseful when one breath analysis device is used by more than oneindividual. In that case, each individual user may calibrate the deviceusing a breath profiling device as described above—in that way, eachuser will generate a recognizable exhalation pattern, or fingerprint,that the breath analysis device can recognize. The breath analysisdevice may receive calibration data from a breath profiling device formore than one user, such as two, three, four, or even more users, andstore that calibration data relating to each user. Thereafter, theseexhalation fingerprints may be used to differentiate between users. Forexample, a breath analysis device may accept exhalation characteristicdata (i.e., the exhalation fingerprint) for four separate individuals.When one of these four exhalation-fingerprinted individuals uses thebreath analysis device, the breath analysis device compares one of moremetrics associated with the user's exhalation (e.g., volume, flow rate,temperature, carbon dioxide concentration, oxygen concentration, etc.)to the breath analysis device's database of exhalation characteristics(i.e., the four separate exhalation fingerprints) and automatically(i.e., without user involvement) identifies the user based on thatcomparison.

As different users have different respiratory track anatomies, it may beadvantageous for a device to be able to adjust to an individual user(based on such variables as sex, height, and age) so as to adjust avented or exhausted portion of a breath in relation to the analyticalportion. This may be done automatically by using look-up or data tablesor user calibration, as discussed above. However, user input may also beaccepted to change the volume ratio of exhausted exhalation toanalytical portion. In some embodiments, the user adjusts a mechanicalsetting or portion of the device. In other embodiments, the user inputsa selection or setting into the device (or another peripheral that is insome form of communication with the device, e.g., wired or wireless datacommunication). Based on that user input, the device responds to varythe volume of the exhalation that is discarded.

“Within User” Variation Problem and Solution

There may be a significant difference in the exhalation characteristicsacross a population which is primarily driven by sex, age, height,sickness (e.g., the flu) or disease (e.g., chronic emphysema). Forexample, a normal, healthy adult male in his late 20s and a normal,healthy adult woman in her 70s have difference tidal volumes (571 mL v.367 mL) and forced vital capacities (4.70 L v. 2.85 L).

Another complicating factor may be that a given individual's exhalationcharacteristics may change based on changes in health. A common symptomof the flu is difficulty breathing. Nausea or upset stomach may impairdiaphragm contraction. Dental work may impact the ability to fully openthe mouth (thereby adding flow restriction). Allergies or runny nose maycause shallow breathing. It is still desirable to properly capture analveolar sample and conduct an analysis of the alveolar breath sampleduring these times.

A further complicating factor is that breath analysis devices arefrequently designed to be small and portable (as discussed elsewhereherein). The mouthpiece is also frequently small. Within a breathanalysis device, there are likely sensors, desiccant or flow sensorsthat contribute to enhanced flow resistance. As such, the actual volumethat a user exhales may be substantially less than the user's forcedvital capacity (e.g., it is not 2.85 L or 4.70 L from the examplesabove). In the case of Mylar bags used in the breath collection field,for example, some generally healthy “normal” individuals are unable tofully inflate a 1 L bag. As such, depending on the level of flowrestriction, the “dead air” space may be a significant portion of theoverall available breath sample.

Yet another complicating factor is that not all users properly exhaleinto a device. There are instances in which a user may cough, expendsubmaximal effort, have a “slow start”, not be at rest, not have accessto total lung capacity (TLC) at the start of the test, etc.

For these reasons, among others, it may be desirable to profile the userperiodically in case an adjustment to the measurement is needed.Alternatively or in addition, it may be desirable to associateexhalation characteristics with the breath result so that adjustmentscan be made based on an atypical relationship between the breath resultand the exhalation characteristic. Lastly, it may be desirable to flagcertain measurements or display an error message if the user doessomething that could cause an improper result, such as coughing mid-waythrough the test. Examples of devices that use these principles aredescribed below.

In one embodiment, a breath analysis device senses one or more real timeexhalation characteristic (e.g., flow rate, pressure, exhalation time,temperature, etc.) that may be used to control inflow into the analysisdevice, for example using a valve. These characteristics are logged inthe breath analysis device together with the associated acetonemeasurements. This logged information could later be used to, forexample, discard or discount aberrational analyte measurements (e.g.,acetone measurements), or to adjust these measurements to compensate fordeviations in how the user exhaled. A learning algorithm could alsoanalyze the log and associated measurements to determine appropriatecompensation factors for the user.

In another embodiment, the breath analysis device could use storedbreath profile information to determine whether the user exhaledproperly into the breath analysis device, and could abort the test (orperhaps flag the result as aberrational) if the exhalationcharacteristics do not sufficiently match the user's stored breathprofile.

In one embodiment, the user is prompted to re-profile based on (a) usersuggestion that re-profiling is needed or desirable, (b) informationgleaned from the user's location, calendar or other health informationsuggesting that the user is sick or has made a respiratory impactfulchange, such as started using an inhaler, or (c) a historical change incertain characteristics such as the duration or rate of exhalation.Re-profiling may occur via an App alone (e.g., the app shown in FIGS.69A-D), a trainer that is separate from the device, or the deviceitself.

The user provides an initial breath sample via a capture mechanism. Thecapture mechanism may be comprised of the device itself, which containsa two flow path system, each containing a flow sensor. As the breathsample passes through the first restrictive path, the flow sensor willindicate various traits regarding the breath sample and create thebreath profile for the user. Because a flow sensor is utilized, themobile interface relationship may be minimal during the profilingprocess. The interface can instruct the user to breath into the device,and the flow sensor can record the rest of the information, such as thestart and end of the test and change in flow rates. During a functionalbreath analysis test, the breath profile can indicate to the device thetime at which the sample should travel through the next flow path. Thisis achieved by instructing the device to expose another flow channel,creating a new path of less resistance for the sample to travel through(and, possibly, close the first flow channel).

In another embodiment, the device and capture mechanism are separated.The capture mechanism is comprised of a mouthpiece with resistance thatis comparable to the device, in order to simulate an actual device test.This capture mechanism, or “trainer,” can facilitate the collection of asample for profiling the user's breath, and is also connected to themobile interface. The mobile interface can instruct the user on when tostart and stop the delivery of a sample through the trainer. The startand stop measurements can help estimate how it long it takes the user toevacuate their entire lung volume, which was be correlated to forcedvital capacity, tidal volume, etc.

In another embodiment, the device and capture mechanism are separated.The capture mechanism is comprised of a resistive mouthpiece, whichcontains both a flow sensor and a clocking feature. The clocking featurecan record the time at which a breath began to travel through a flowpath, and when it ended. The flow sensor can provide the rate of gasflow. In this embodiment the mobile interface can be minimal during theprofiling process. The mobile interface will instruct the user tobreathe through the trainer, and the mouthpiece components can generatethe rest of the flow characteristics.

Valve Shutoff Problem and Solution

For embodiments that involve closing flow paths at different timesduring the exhalation, it is important to note the timing constraints ofthe closing process. For example, a user may comfortably exhale througha medium or high flow resistance device for only 10 seconds. However, ifa gear-based linear actuator is used, it may take 2-3 seconds toactually close the flow path. Thus, a significant portion of the samplemay be undesirably lost due to a “slow-closing” valve.

The sum of the time (a) to generate the closing signal based onexhalation properties such as temperature, CO2 concentration or otherparameters, (b) to communicate the signal to the valve, and (c) to closethe path using the valve should be minimized so that an alveolar breathsample can be captured within the duration of a single exhalation by theuser. Candidate solutions include solenoid valves or magnetic actuationof a metallic valve.

Another solution may be to know the closing time a priori and thus avoidthe time to generate the closing signal or the time to communicate thesignal to the valve. A priori determination may be based on known usercharacteristics (e.g., age, sex, height, weight), medical history orstate (e.g., obstructive or restrictive breathing), prior measurement(using a profiling device that looks at exhalation characteristics), ora user setting (e.g., the user selecting a dial or inputting a valuesetting forth the time to close the valve).

Compensation Challenges

In effect, there are two “volumes” that need to be optimized: (a) thevolume of the breath sample that should be vented and not analyzed, and(b) the volume of the breath sample that is necessary for analysis sothat the sensor generates an accurate reading.

It may be that the flow resistance through the bypass flow path and themain sensing flow path will be different. While a first set ofcharacteristics are instructive to determine when to switch from thebypass flow path to the main sensing flow path, a second set ofcharacteristics are needed to ensure that the user exhales a sufficientvolume through the main sensing flow path. In this regard, if a user canonly exhale 1000 mL, the sensor requires 750 mL and the “dead volume” is450 mL, the device may need to “vent” only the first 250 mL and then beaware that 200 mL of dead volume is being mixed with the 550 mL ofalveolar air to generate the 750 mL sample. In this situation, thedevice may need to compensate by increasing the measured response by36%. This is further complicated by the fact that the first 250 mL ofvented air may be easier for the user to exhale because there is lessflow resistance in the bypass valve. Accordingly, the total volume thatthe user is expected to generate is:V_(tot)=Q_(bypass)*t_(bypass)+Q_(sensor_path)*t_(sensor_path), where Qis flow rate, t is time and V_(tot) is the total volume through thedevice.

Example of Parameter Change by Device

In some embodiments, a particular device can be programmed with certain“breath profile” parameters, based on inputted factors such as age,height, weight, etc. As is discussed elsewhere herein, the breathanalysis system may communicate with a mobile interface and acceptparameters or other programming from such mobile interface. The breathprofile can help determine total expired volume of a user, as well aswhat volume of air needs to be vented, in order to receive a deepalveolar lung sample.

As an example, consider two users, referred to as User A and User B.User A is a 70 year old female, and User B is a 25 year old male. UserA's breath profile indicates a total expired volume of about 1.5 L and asubsequent dead space of about 100 mL that requires venting. Due to age,user A exhales with less force and pressure. This translates into aslower flow rate. User B is a healthy athlete with a breath profileindicating a total expired volume of about 4.0 L and a subsequent deadspace of 750 mL that requires venting. User B expel their totalexpiratory volume in about 1-2 seconds.

In the case of User A, user A's device would utilize a solenoid valvethat is controlled by a processor. This valve would be instructed by theprocessor to pivot and create a completely open flow path. This pathwould remain open for about 5 seconds, which would translate to theevacuation of the user's dead space. After about 5 seconds, the solenoidvalve would close and allow the breath sample to flow through asecondary flow path which contains the disposable cartridge. The valvewould then remain closed for the duration of the sample collection.Alternatively, the valve can be activated by the user using a buttonmechanism that when pushed, exposes the first flow path. Due to theuser's lower expiration rates, the device likely has enough time toaccurately switch between flow paths during the test.

In the case of User B, expelled air can be hard to control in anautomated device due to their higher expiration rates. If User B isknown to expel their total expiratory volume in 1-2 seconds, their flowpath may need to be restricted in order to create a longer dwell timethat is manageable by the device. User B's device could use the samesolenoid valve used in User A's example, however the processor wouldinstruct the valve to pivot at a lower angle and create a flow path thatis “halfway” open. Such a restrictive path would allow less air totravel through (i.e., would force a lower flow rate). Therefore, thevalve could remain open for about 3 seconds (longer than it would takeUser B to fully exhale in the absence of any flow restriction) toevacuate the dead space volume. After about 3 seconds, the solenoidvalve would close and deliver the rest of the breath sample to thedisposable via a secondary flow path. The remaining volume (e.g., theanalytical volume) may be delivered to the disposable without flowrestriction, or while maintaining the “halfway” open flow path.

FIG. 70 shows a breath capture device (e.g., a device such as might beused in the example immediately above) that communicates with aprocessor 10005. The processor controls a solenoid valve 10015, which ismanipulated through the use of an actuating mechanism, e.g., a linearactuator 10020. The processor receives various inputs from the processorin order to perform an analysis.

When in an unactivated mode (A), the solenoid valve blocks one of twoflow paths within the device. Following the path of least resistance,the breath sample will first flow through the second flow path 10025.The second flow path is comprised of a porous barrier 10030 thatprovides less resistance then the closed butterfly solenoid valve, aswell as flow sensor 10035. The flow sensor 10035 measures how much airis going through the second flow path 10025 and communicates this to theprocessor, which then causes the solenoid valve to close the flow pathwhen the desired vented volume has been evacuated.

After the evacuation of the desired vented volume, the device is in adifferent mode (B). In this mode, the processor 10005 instructs thelinear actuator 10020 to retract, thus pivoting the solenoid valve10015, and opening up the first flow path 10040. This first flow path10040 now provides less resistance than the original porous barrierfound in the second flow path. This flow path is coupled to a sensingelement, such as colorimetric breath acetone analyzer. The first flowpath also contains a flow sensor 10045 that determines when the gasdelivery to the disposable cartridge is sufficient. The top and bottomof sections A and B contain perspective drawings of the device from thefront and back, respectively.

FIGS. 71A and 71B show a breath capture device that operates usingmechanical principles. In this embodiment, the solenoid valve 10105 isattached to a linear actuator 10110 that is controlled by a dial 10115.This dial is attached to gear 10120 that can be manipulated by the user.The gear 10120 contains various levels or notches that the user can set.The rotation of the gear directly influences the pivot angle of thesolenoid valve 10105, which can provide variations in between the openand closed scenario identified in FIG. 70 . As an example, if aparticular user only required half the normal sample volume in order tocomplete the test, the solenoid valve could open “half-way” to lead to asemi-restrictive flow path. Similar to the embodiment illustrated inFIG. 70 , this embodiment utilizes flow sensors 10125, 10130 in bothflow paths 10135, 10140 to determine when the desired vented volume hasbeen evacuated, when to switch flow paths, and when a test has beencompleted. The top and bottom of sections A and B contain perspectivedrawings of the device from the front and back, respectively.

User training and or preparation for exhalation may be accomplished inany of a number of ways. Some types of user training function simply toprepare the user for their ultimate exhalation. For example, acollection device or cartridge may be a bi-directional “whistle” thatcan accept exhalation into either end. In such devices one end may be a“dummy” end, while the other end is the analysis end. In someembodiments, the dummy end does nothing but accept exhalation. Such afeatureless dummy end can simply allow the user to get in the mind-setof exhalation, e.g., thinking about how to properly exhale to satisfythe analytical portion's requirements). In other embodiments, the dummyend senses one or more characteristics of the user's exhalation. Forexample, the dummy end senses that the user has actually performed atleast one practice exhalation. In some embodiments, the analysis endincludes a valve that prevents the user from exhaling into the analysisend until the dummy end has detected at least one practice exhalation.In much the same way, the dummy end may respond (e.g., signal the useror allow exhalation into the analysis end) once the user has performed anumber (e.g., 1, 2, 3, 4, or more) of correct exhalations (e.g.,exhalations that satisfy the exhalation required by the testingparameters). Such a user training system may help to ensure that eachand every test cartridge is used to the fullest of its potential andthat no cartridges are wasted or false results produced due to improperexhalation by the user.

To more effectively separate different breath segments (e.g., I, II, IIIand IV, or combinations thereof, from FIG. 4 ), a system can utilizedifferent potential triggers. In one embodiment, the system analyzes thevolume of breath passing through the device. The first portion of breaththat is exhaled is “dead space”—e.g., air from the mouth and uppertrachea. In some embodiments, it is desirable to capture breath that isdeeper in the respiratory tract as that air has been in more directcontact with the blood from which volatile organics will evaporate. Inthis case, the device could utilize a timer to determine how much volumeof breath has passed through the device. A timer would be used if theuser's flow rate is constant or above a certain level. If that flow rateis known, then it need only be multiplied by time to determine how muchbreath has passed through the device. In general, for an adult, analveolar breath sample occurs after about 230 ml of breath. In anotherembodiment, the system would begin to take an alveolar breath sampleafter about 300 ml of breath have been passed through the device. Thiswould insure that an alveolar sample is collected, but may reduce theprecision of the device.

In another embodiment, the system measures temperature to determine whenan alveolar breath sample has been obtained. A device can measuretemperature with a thermistor or any other appropriate temperaturemeasuring device. Systems based on temperature sensors may requireambient temperature as a reference. Breath that is close to the blood(e.g., breath that is in the lungs) will be at about body temperature(roughly 37° C.). Atmospheric gas (e.g., air), on the other hand, shouldbe close to or at the ambient temperature. In one embodiment, the devicedirects breath to a reactive chamber only after or when it detects thatthe breath's temperature is about 90% closer to the body temperaturethan the ambient air temperature. For example, if the outsidetemperature is 25° C. and the individual is at 37° C., designate thesample at 0.9*(37° C.−25° C.)+25° C.=35.8° C. This should help to ensurethat substantially only alveolar breath is collected.

In another embodiment, the system measures the carbon dioxideconcentration to determine when an alveolar breath sample should beobtained. FIG. 58 shows a graph of the general relationship betweencarbon dioxide concentration as a function of the amount of air expired.Around about the exhalation of 250 ml to 300 ml of breath, theconcentration of carbon dioxide increases rapidly and then remainsapproximately constant, regardless of the volume of expired air. Asshown in FIG. 59 , carbon dioxide concentration is significantly higherin alveolar air than atmospheric or expired air—this is because carbondioxide is produced as the body metabolizes fuel substrates. In fact, asshown in FIG. 59 , atmospheric air comprises only about 0.04% carbondioxide, well below half a percent. By contrast, expired air comprisesbetween about 3.6 and 5.3% carbon dioxide. Using these approximations,it can be seen that expired air has between about 7 and 130 times theconcentration of carbon dioxide as does atmospheric air. In oneembodiment, the system may include a carbon dioxide sensor in line withthe exhalation pathway. In one embodiment, the device directs breath tothe reactive chamber only after or when it detects that the carbondioxide concentration is a concentration indicative of the desiredbreath segment (e.g., for alveolar air it is between about 3.6% or5.3%). This should help to ensure that substantially only alveolarbreath is collected.

In another embodiment, the system measures the oxygen concentration todetermine when an alveolar breath sample should be obtained. Withcontinued reference to FIGS. 58 & 59 , oxygen concentration issignificantly lower in alveolar air than atmospheric or expired airbecause oxygen is consumed as the body metabolizes fuel substrates. Inaddition to showing the relationship between carbon dioxide and volumeof air expired, FIG. 58 shows a graph of the general relationshipbetween oxygen concentration as a function of the amount of air expired.Around about the exhalation of 250 ml to 300 ml of breath, theconcentration of carbon dioxide decreases rapidly and then remainsapproximately constant, regardless of the volume of expired air. This isbecause oxygen is absorbed at higher rates the deeper into therespiratory tract—the trachea absorbs dramatically less oxygen frominspired air than do the alveoli. As shown in FIG. 59 , oxygenconcentration is lower in both alveolar and expired air than inatmospheric—this is because oxygen is consumed as the body metabolizesfuel substrates. In fact, as shown in FIG. 59 , alveolar air comprisesonly about 13.6% oxygen. By contrast, expired and atmospheric aircomprise about 15.7% and 20.84% oxygen, respectively. While not as adramatic difference in concentrations as is observed with carbondioxide, this change in concentration may also be used to segment orfractionate a breath. In one embodiment, the system may include anoxygen sensor in line with the exhalation pathway. In one embodiment,the device would direct alveolar breath to the reactive chamber onlywhen or after it detects that the oxygen concentration is around lessthan about 15.7% or 13.6%.

In yet another embodiment, the system measures another analyte todetermine when to collect any given breath sample, e.g., when analveolar breath sample should be obtained. For example, certain analytesmay be predominantly present in alveolar breath segments. Alternatively,other analytes may be predominantly present in tracheal breath segments.The presence or absence of such analytes can be used to determine if abreath segment from the alveoli or the trachea is being analyzed. FIG.59 lists the relative amounts of various analytes at different segmentsof breath. This information can be used to by a sensor in line with theexhalation pathway.

In another embodiment, the system may aggregate information over time ofthrough calibration of a user's history. Once a user is trained toproperly exhale through the device, the user's prior history may be usedto determine if an alveolar sample (or other desired sample) has beencollected. As one simple example, that data or user history may includewhen that user's exhalation begins to include alveolar breath based onany of the preceding methods done over many uses. In one embodiment, thesystem includes a process that stores or can access data, e.g., a userhistory log. In some embodiments, the device may compare a present datavariable(s) (e.g., one or more of temperature, carbon dioxideconcentration, oxygen concentration, time, flow rate/volume, etc.) tothe user's history: if the present data variable(s) falls within anacceptable margin of error (e.g., a previously determined acceptablemargin of error), the device accepts the test as valid; if the presentdata variable(s) fall outside the acceptable margin of error, the devicediscards the test as invalid (e.g., stamps a chip associated with thattest) so that the test is not ultimately used. Of course, validating auser's test based on an increasing number of variables may tend toimprove the likelihood a test identified as valid is, indeed, valid. Inthat case, it is likely that the number of false positive test resultswill decrease. However, as the number of variables increases, the numberof valid test results will likely decrease because one or more of themultiple variables being compared may be outside of an acceptable range.In this case, it is likely that the number of false negative testresults will increase. Acceptable values may be tailored to the user anapplication by varying the number of compared variables (i.e.,increasing or decreasing the number of variables) as well as theacceptable margins of error (i.e., increasing or decreasing theacceptable margins of error).

In another embodiment, the system may use user input to determine whenan alveolar sample has been collected or when alveolar breath should bedirected to the reactive chamber. Information such a population data ordata from other equipment, e.g., spirometry, can be inputted by the userto assist. In another embodiment, the user may input the time (e.g., 2seconds) as the time when alveolar breath should be directed to thereactive chamber.

In some embodiments, the system monitors the user's exhalation andsignals the user when to capture a sample, e.g., a deep lung sample. Forexample, a user may simply be exhaling into the system at which time thesystem registers the commencement of the user's breath. The user may betrained to continue exhaling into the device. Based on factors,parameters, and data discussed elsewhere herein (e.g., time, volume,temperature, carbon dioxide concentration, oxygen concentration, or acombination of any of these), the system identifies the segment ofinterest of the user's breath and signals the user when that segment isreached or ready for collection. In some embodiments, the system signalsthe user minimally in advance of when the sample is ready for collectionso that none of the sample is accidentally discarded as exhaust gas. Forexample, the system may signal the user in advance of sample collectionby a time of about 0.25 seconds, 0.5 seconds, 0.75 seconds, 1 second, ormore than 1 second, depending on the user and the desired sample. Thesignal provided or given by the device to the user may be any of avisual, auditor, or haptic signal. For example, for a visual signal thedevice may have an LED (or any other type of light) that changes color(e.g., from red to green), blinks, turns off, gets brighter, or dims.Alternatively, for an auditory signal the device may have a speaker thatbeeps, makes a tone, increases in volume, decreases in volume, increasesin pitch, or decreases in pitch. Finally, for a tactile signal thedevice may have a buzzer that vibrates, buzzes, or shakes. Once thedevice has signaled the user that they have reached the appropriate timeto collect the desired sample or segment, the user may interact with thedevice to take the sample. For example, in some embodiments, the devicehas an analysis end and a dummy end (as discussed above): when thedevice signals the user, the user stops exhaling into the dummy end andbegins exhaling into the analysis end (e.g., substantially immediately,or as quickly as possible). Alternatively, the user may push a button orflip a switch that changes the flow path from an exhaust route to ananalysis route.

FIGS. 72A and 72B show an embodiment of a breath capture device thatinvolves interaction with the user to switch the flow path. In thisembodiment, the processor 10210 does not directly attach to the solenoidvalve 10215, and instead contains an indicator 10220. As discussedabove, this indicator 10220 can be in the form of an LED light or othervisual notification, or can also be a speaker that emits an audioindicator for the user. The first flow path 10225 in this embodiment iscomprised of a butterfly valve attached to a finger pedal 10230 orlever, and a mass flow sensor 10235. In an unactivated mode (FIG. 72A),the breath sample travels through the second flow path until theindicator is activated. This indicator serves the purpose of notifyingthe user to push the level, thus exposing the first flow path. Thisindicator remains active, to let the user know to keep the first flowpath open until the test is over, symbolized by the turning off orinactivation of the indicator. This embodiment does not allow for anyvariations in the resistance of the first flow path. The top and bottomof sections of FIGS. 72A and 72B contain perspective drawings of thedevice from the front and back, respectively.

FIGS. 73A and 73B show another breath capture device that involvesinteraction with the user to switch the flow path. Here, the systemincludes a mobile interface and processor. Similar to the example inFIGS. 72A and 72B, this embodiment also utilizes an indicator. In thisembodiment, however, there are two flow paths that are identical, withthe exception that one flow path would be attached to the disposablecartridge. Both flow paths remain open at all times. Flow paths arealternated by physically rotating the device, and breathing into thealternative flow path. In an unactivated mode (FIG. 73A), the samplewill travel through the flow path that does not contain the disposablecartridge until the flow sensor indicates that the dead space has beenevacuated. At this time, the flow sensor input will be received by theprocessor. The processor activates or turns on the indicator. This willnotify the user to rotate the device and deliver sample through thesecond flow path, and through the disposable cartridge. The indicatorturns off at the end of the test, notifying the user to discontinuebreathing into the device. The top and bottom of sections of FIGS. 73Aand 73B contain perspective drawings of the device from the front andback, respectively.

In addition to separating the desired vented volume from a desiredalveolar volume, the separate flow paths can be utilized in otherapplications. As an example, two users can operate from the same device.When a flow path has been switched or rotated, the processor can operateunder a different breath profile. Under this application, each separateflow path may end in a cartridge. The flow sensor and indicator can beutilized to tell the user when to attach and remove the disposablecartridge. The cartridge would be attached after the desired ventedvolume and removed at the end of a test.

Alternatively, the two separate flow paths can facilitate two differenttests for a single user. Under this application, each separate flow pathmay end in two different cartridges, for example, one (1) acetonecartridge and one (1) ammonia cartridge. The flow sensor and indicatorwould be utilized to instruct the user when to attach and move thedisposable cartridge. Different variations of the indicator (forexample, differently colored lights) can be utilized to determine whenswitch to rotate the device and begin a new test.

The breath analysis system preferably comprises an air fractionator thatseparates the breath sample into different segments or fractions ofinterest. Exemplary apparatus and methods to achieve this are disclosedelsewhere herein as well as in U.S. Patent Application Ser. No.62/247,778, which is hereby incorporated herein by express reference asif fully set forth herein.

Signal generation can be accomplished using a wide variety of knowntransduction techniques in conjunction with appropriate sensors.Examples include, but are not limited to: colorimetric analysis ofchemical reactions measured by reflectance, colorimetric analysis ofchemical reactions measured by absorbance, fluorescence analysis ofchemical reactions measured by lifetime analysis, analyte-nanoparticleinteractions measured by resistance/impedance analysis, electrochemicalanalysis of chemical reactions measured by chronoamperometry, gasconcentration analysis by laser absorbance, and many others.

The manner in which the breath sample is obtained and the profilesegment definitions and demarcations can have a significant impact onthe quantity and quality of information that can be obtained.

There are a plethora of different breath profiles. Breath is also richwith different analytes. In addition to selecting chemistry,transducers, environmental controls, etc. to facilitate the analysis ofa particular analyte, it is also important to select a breath profilethat is of significance to the analyte of interest.

Selecting the appropriate breath profile for a particular analyterenders more meaningful information than analyzing all analytes using ageneric breath profile. For example, nitric oxide may be present in thebloodstream and thus in alveolar air as equilibrium is achieved betweenthe breath and blood. However, nitric oxide may also be generated in thebronchial tubes in the event of airway constriction due to conditionslike asthma.

The breath profile may be the natural result of the breathingcharacteristics of the patient, for example, as when a patient is askedto merely breath normally into the device. Alternatively, in someinstances it is desirable or necessary for the patient to be instructedon what breathing profile he or she is to use. For example, it may bedesirable for the patient to inhale maximally before a breath isdelivered to the breath analysis device. Other examples of patientinstructions or user-modified breathing profiles include rapidexhalations, slow and steady exhalations, shallow inhalations, deepexhalations with shallow inhalations, etc.

In light of this, it may be advantageous in some instances to provide apatient assist device, which may be any apparatus that aids the patientin conforming to a breath profile. For instance, a patient assist devicemay be a flow restrictor that is designed to help the patient breath ina consistent manner. Patient assist devices are increasingly significantif the breath profile is complex or if the patient has a hard timefollowing directions.

Preferably breath profiles are used in conjunction with a plurality ofbreaths (e.g., multi-breath analysis), whether rebreathing ornon-rebreathing.

Under certain circumstances, it may be useful to display information tothe user regarding the status of the analysis, e.g., breath profile.This information may be provided during the analysis process, e.g., agraph showing the user what to do next, or at the end of the analysis,e.g., providing instruction to the user that he or she did not performthe test correctly for one or more of the breath profiles.

The breath analyzers may and preferably will also include an interfaceby which the device may instruct the user what to do next. This isparticularly significant if a complex breath profile is required, suchas the breath profile described in FIG. 15 . The device may, andpreferably will, position sequential breath profiles in the order ofhardest to easiest or requiring the most to least concentration toaccount for diminishing attention or reduced compliance over time by thepatient. In other words, if breath profile A is the most difficult as itinvolves multiple re-breaths and it also provides the most criticalinformation, the software incorporated within the device may provideinstruction such that breath profile A is performed prior to breathprofile B, C, and D. Yet another ordering scheme has to do with orderingthe tests such that one test does not interfere with the next. Forinstance, forced expiration may cause error to computation of therespiratory quotient (RQ). Accordingly, if forced expiration is usefulfor measurement of a particular analyte, this may be performed after themore relaxed breathing for RQ.

Example of Detection of Diabetes Onset Using Breath AcetoneConcentration

To illustrate certain aspects of at least one embodiment of theinvention, consider the following example. A physician suspects apatient is suffering from the onset of diabetes. Acetone in breath hasbeen correlated with fat metabolism, and can be used to identifymetabolic issues associated with the onset of diabetes. The physiciantherefore seeks to use a breath analysis device to analyze the patient'sbreath for this analyte using apparatus (4) appropriately configured forthis test, as described elsewhere herein.

A suitable test for breath acetone is a normal, single breathexhalation, such as that shown in FIG. 3 . This breath profile isselected and/or preprogrammed into processor 38 of apparatus (4).

Breath acetone appears in the breath endogenously through fatmetabolism. The acetone, being a volatile organic chemical, travelsthrough the vascular system into the lungs, where it permeates the lungtissue and enters the deep alveolar spaces. As it accumulates in thedeep alveoli, it diffuses into the general alveolar space, but typicallydoes not infiltrate into the upper airways, at least not in significantconcentrations. Accordingly, the processor of apparatus (4) has beenpreviously programmed and configured to segregate the breath profileinto four segments (roman numerals I through IV), corresponding to theupper airways (post tracheal airways (I) and bronchial spaces (II)),general alveolar spaces (III) and deep alveolar spaces (IV). Theprocessor is also preprogrammed to select segments III and IV as thoseof interest based on the expectation of their relatively higherconcentrations of acetone. Note that, instead of preprogramming,apparatus (4) may be configured to allow the user to select theseinputs, e.g., using a user input such as a key pad, keyboard, or thelike.

Acetone in the selected gas fraction can be measured through a varietyof means. Preferably, an acetone sensor is comprised of a disposablereactive volume of chemically-coupled silica gel particles housed in ahand-held cartridge. Acetone in a gas sample flowing over the silicaparticles adheres to the silica gel and reacts to form a colored productwhen in the presence of a reaction-promoting solution. A color camera orother light-sensing device, preferentially with spatial resolution, canbe used to quantitate the color change and to correlate that change toacetone concentration.

The subject is then asked to exhale into the mouthpiece. In its initialstate, the valving device is in its closed position. As the subjectexhales into the device, pneumotachometer or alternative flowmeasurement device 18 provides pressure and velocity information to theprocessor. As pressure increases from its initial value, the processorcauses the valving device to move from its initial closed position tothe second open position, whereupon the initial portion of the breathsample is vented via the conduit and the exhaust conduit out of theapparatus. As the breath sample input proceeds, the processor traces outthe breath profile and divides it into the four segments noted above.

When the processor identifies the transition from segment II to segmentIII, it causes the valving device to move to the first open position,whereupon the breath sample is directed via the conduit to the reactioncavity and the sensor. Acetone present in the breath sample contacts thereactive surface or component of the sensor, where it reacts and asignal representative of the concentration of the acetone is generated.This signal is communicated to the processor, which then generates acorresponding output of this sensed information on the display. In someembodiments, the device (e.g., breath analysis device) senses one ormore real time exhalation characteristics (flow rate, pressure,exhalation time, temperature, etc.) that are used to control the valve.Such characteristics may be logged in the breath analysis devicetogether with any associated acetone measurements. Logged informationmay later be used to, for example, discard or discount aberrationalacetone measurements, or to adjust these measurements to compensate fordeviations in the user's exhalation pattern. Additionally, the devicemay also incorporate a processor that runs a learning algorithm toanalyze the log and associated measurements to determine appropriatecompensation factors for the user. Examples of various compensationfactors are described in U.S. patent application Ser. No. 14/690,756,filed Apr. 20, 2015, now U.S. Pat. No. 9,486,169, which is herebyincorporated by express reference as if fully set forth herein,

As the exhalation attenuates and the flow velocity reduces below athreshold level as detected by pneumotachometer or a flow measurementdevice, the processor causes the valving device to return to the secondopen position, thus stopping the flow into the reaction cavity andcausing it to be vented via the conduits. When flow stops, the processorcauses the valving device to close to avoid backflowing ambient air intothe apparatus (4) if the subject then inhales through it.

Example of Fractionation of a Breath to Detect Analytes in SeparateBreath Segments

Multiple analytes in a single exhalation can be quantified in a mannersimilar to that described herein. In this case, however, provisions mustbe made so that a gas sample, sufficient to be split amongst themultiple sensors, can be directed to those sensors in sequence or inparallel. In some cases, a sampling protocol may require the collectionof gas fractions from different anatomical regions; in other cases, theanatomical region to source the samples can be the same. An example of aflexible system capable of measuring 4 different analytes from fourphysiological regions in a single breath is shown in FIG. 25 . In thisexample, a user breathes into a breath input device and the exhaledpressure is measured using a pressure transducer. The exhaled volume andflow rate are also measured using a pneumotachometer or alternative flowmeasurement device. At the required time, the first valve in a valvearray is opened, allowing the first bag of a bag array to fill with gascorresponding to physiological region I. The other bags are filled insequence until all bags are filled with samples from distinct regions.Each bag can then be evacuated in sequence and directed to sensors for asingle analyte or multiple analytes, depending on the needs of themeasurement and the available hardware. Some embodiments make use ofmultiple and/or separate sensors, e.g., a sensor for acetone and asensor for ammonia. The gas from a particular region is evacuated fromthe bag and the contents are passed over a chemically reactive columnfirst for acetone and the resultant color change (in response to analyteconcentration) is measured with a camera. A second portion of gas issent to an ammonia column. Up to four different analytes (or the sameanalyte from four separate regions) can be measured from a single breathin this manner.

As the volumetric capacity of the human lung will vary from individualto individual, more significant results may be obtained by firstmeasuring the maximum exhaled volume of an individual and dividing theexhaled air into fractions by the percentage of maximum volume that hasbeen exhaled.

Example of Analysis of Complex Combination of Other Breath Profiles

Multiple breath profiles include rebreathing and non-rebreathingmodalities. These are illustrated in FIGS. 12A and 12B. In FIG. 12A, avalve is used to assist in the capture and containment of breathsamples. With the valve open, the subject can re-breathe the air in thebag, thus accumulating volatile compounds and allowing the individual tobreath in a natural fashion. When the sampling is completed, the valveis shut. In FIG. 12B, a non-rebreathing sampling scheme is depicted. Inthis case, two one-way valves combine to form a non-rebreathing valvesuch that inhalations of the subject draw air from the ambient, whereasexhalations push air into the collection bag. An optional valve at theoutlet of the bag allows breathing to continue indefinitely to assurecontamination-free concentrations of exhaled breath.

A breath profile may also be a complex combination of other breathprofiles. See FIG. 15 . In this figure, the complete breath profilecomprises a normal single exhalation, followed by multiple re-breaths,followed by a single exhalation where the user is instructed to maintaina steady flow.

The above method is preferably repeated for a plurality of analytes.

FIG. 3 is a flow chart demonstrating a method for operating a breathanalysis device using multiple breath profiles. Step 1 prompts for theuser to identify an analyte of interest. Step 2 prompts the user tospecify a breath profile. Step 3 prompts the user to input whetherfurther analyte-breath profile combinations are desired.

FIG. 1 is a breath analysis device that comprises feedback to thepatient regarding compliance with a breath profile. A patient configuresa breath analyzer by using the keyboard to input the desired analyte ofinterest and the desired breath input. The display appears to providefeedback to the patient as to whether the patient is complying with thedesired breath profile. Once the patient has configured the device, thepatient exhales through the breath input and the breath is directed tothe analysis portion of the device. The analysis portion may comprise avalving system and/or a sensor.

Preferably, the analyzer is conducive to field analysis, or otherwise tomake such assessment without a requirement for expensive and cumbersomesupport equipment such as would be available in a hospital, laboratoryor test facility. It is often desirable to do so in some cases with alargely self-contained device, preferably portable, and often preferablyeasy to use. It also is necessary or desirable in some instances to havethe capability to sense the analyte in the fluid stream in real time ornear real time. In addition, and as a general matter, it is highlydesirable to accomplish such sensing accurately and reliably.

FIG. 13 depicts a system that could be used to automatically fractionatethe expired air into samples I and II (not necessarily corresponding tothe theoretical regions I and II as discussed earlier). An automaticthree-way valve directs expired air to either bag I or II. Note that forthis to be successful, the dead volume of the apparatus from the patientmouth to the outlets of the three-way valve must be sufficiently small.This may require an automated 4-way valve, where the patient draws airfrom one port, and then the valve can be automatically switched betweenoutlet port A and outlet port B. An idea for an automated 4-way valveuses a single actuator to control stops on a rod to provide mechanicalhindrance to the passive opening of the standard non-rebreathing valves.

A further refinement of this idea is shown in FIG. 14 . In this figure,the ability of the system to make closed-loop decisions on valve switchtimes is afforded by a high-speed sensor for a gas (carbon dioxide inthe example). When the carbon dioxide concentration in a breathing cyclecrosses a certain threshold, then the automated non-rebreathing valve isactuated. In this way, a patient can sit at the instrument and breathrepeatedly and comfortably. With no intervention from the user, thesystem can fractionate the breath into two components. The contents ofthe bags, in light of both their analytes and the information regardingtheir physiological source, can be of interest.

In certain cases it may be important to control the inhalation depth ofa patient before a breath is expired in order to control the breathprofile. Measuring the pressure at the mouth can be an objective meansto determine when a certain inhalation (or exhalation) volume has beenachieved.

A bag for passively collecting breath fractions from either the upperairways or deep alveolar region is presented in FIG. 26 . With thisapparatus, a breath bag is fitted at one end with a breath inlet and atthe other a one-way valve. The breath inlet contains a spring-loadedball valve, or suitable alternative, such that compression of themouthpiece opens the breath inlet to accept exhaled air and the bag canbe inflated. The one-way valve contains a threaded lock disk such thatthe valve can be configured to open against small amounts of pressure orto be permanently closed. If a deep alveolar sample is desired (orprompted by device software), then the one-way valve lock disk is turnedto allow the valve to crack. A user pinches to release to spring-loadedball valve in the inlet and breathes to inflate the bag. The firstportion of breath is largely displaced by successive portions as theexit valve allows the early breath samples to exit the bag. At the endof an exhalation, the bag is filled primarily with deep alveolar air.Releasing the spring-loaded ball valve traps the sample in the bag untilthe bag is evacuated through the suction of an external pump. If anupper airways fraction is desired, the user turns the lock ring on theone-way valve to close the valve. The user inflates the bag until thebag is filled. The bag is thus filled with upper airway air. Thelock-ring is turned to allow cracking of the one-way valve to enableevacuation of the bag contents through the suction of an external pump.

In accordance with another aspect of the disclosure, a method isprovided for analyzing an analyte in breath of a patient, wherein themethod comprises inputting a first sample of the breath from the patientinto an apparatus as a first breath profile, segregating the firstbreath profile into a plurality of breath profile segments correspondingto anatomical regions of the patient, inputting a second sample of thebreath from the patient having characteristics substantially similar tothe first profile into the apparatus as a second breath profile, andusing the first breath profile to analyze the second breath profileduring at least one portion but less than all portions of the secondbreath profile.

In certain circumstances, it may be desirable to establish a baselinewith a breath profile. Establishing a baseline can be important for anumber of reasons. In the event of expensive reagents, the first breathsample may be obtained to prime the device and the user for the secondbreath sample, which is the one actually analyzed. This may helpminimize unnecessary reagent waste and reduce the overall cost.

In instances of complex analysis, e.g., analysis requiring highselectivity or sensitivity, inputting a first breath sample may enablethe apparatus to lock in certain parameters and limit the subsequentanalysis to those parameters of increased complexity.

Additionally, in the event of an inexperienced, non-compliant, ordistressed patient, the first breath profile may be used to helpdetermine if the user needs further instructions so as to streamline themeasurement process.

Breath analyzers employing the breath profile approach preferablyinclude a volume measurement apparatus. The volume measurement apparatusallows for the breath profile to be studied and allows the device toprovide feedback to the user if the user did not perform the measurementcorrectly. The volume measurement apparatus may be any device or systemthat can determine the flow profile, e.g., a pressure transducer.

The breath analyzers may and preferably will also include an interfaceby which the device may instruct the user what to do next. This isparticularly significant if a complex breath profile is required, suchas the breath profile described in FIG. 15 . The device may, andpreferably will, position sequential breath profiles in the order ofhardest to easiest or requiring the most to least concentration toaccount for diminishing attention or reduced compliance over time by thepatient. In other words, if breath profile A is the most difficult as itinvolves multiple re-breaths and it also provides the most criticalinformation, the software incorporated within the device may provideinstruction such that breath profile A is performed prior to breathprofile B, C, and D. Yet another ordering scheme has to do with orderingthe tests such that one test does not interfere with the next. Forinstance, forced expiration may cause error to computation of therespiratory quotient (RQ). Accordingly, if forced expiration is usefulfor measurement of a particular analyte, this may be performed after themore relaxed breathing for RQ.

Production Rate

In accordance with another aspect of the invention, a method is providedfor obtaining information about a physiological production rate of anendogenous analyte from a breath sample of a patient. The methodcomprises providing an apparatus that comprises a breath input portionand an analysis portion, and inputting the breath sample into the breathinput portion. The breath sample comprises a breath profile comprisingat least one breath, wherein each of the at least one breath comprisinga plurality of segments, and each of the segments of a given breathcorresponds to an anatomical region of the patient that is non-identicalto the anatomical regions for others of the segments. The method alsocomprises analyzing at least one but less than all of the breath profilesegments of each of the breaths of the breath profile to sense theanalyte within the anatomical region or regions corresponding to the atleast one breath profile segments to obtain the information about thephysiological production rate of the analyte, and generating a signal inthe apparatus representative of the information.

Example of Detecting Production Rate of Endogenous Volatile OrganicCompound

In the case of using an apparatus to determine the production rate of anendogenous volatile organic compounds, the manner in which the analysisis conducted and the sample is collected can have profound impact on thesignificance of the information obtained.

FIG. 23 and FIG. 24 present examples of apparatuses that can measure theproduction rate of acetone in the human body, as measured throughbreath. The devices in both figures are the same except for thepositioning and components of the sensor element (items 206, 210, and212 in both figures). Component (202) is a mouthpiece, representing asterile interface to breath collection whereby a user can physicallyinteract with the instrument. Component (224) is an anti-viral/bacterialfilter, which provides protection from cross-contamination between theuser and the instrument. Component (222) is a breathing hose, presentinga gas line between the user and the instrument without imposing asignificant breathing resistance onto the user. Component (220) is aflow measurement device that imposes a low breathing resistance to theuser. Item (220) can be any device that measures flow and that imposesminimal obstruction to breathing. For resting measurements, the flow ispreferably in the range of 5-20 L/min. Examples of candidate devicesinclude: a heated Fleisch pneumotachometer, a Lilly-style tachometer, anultrasonic flow transducer, and a turbine flow meter. Component (204) isa mixing chamber, a vessel that allows a sufficient store of mixedexhalation gases to accumulate so as to allow accurate sampling of thegas measurement equipment, described next. Components (206, 210, and212) comprise a gas sampling line, whereby a pump (212) removes gas fromthe mixing chamber (204) and pushes it through a flow measurementelement (206) and a sensor element (210). A separate gas sampling line,with its own motive force (pump), is desirable to divorce sensor gassampling from user breath input. In certain sensor configurations,particularly packed bed columns, a significant restriction to breathingis imposed by the sensor element. It is desirable to maintain breathingresistance as low as possible for user comfort, and thus a separatesample line allows the breath collection to be designed for optimal userinterface, completely independent of sensor requirements which include,in general, known and steady flow rates and constant gas line pressures.

FIG. 23 and FIG. 24 differ in the placement and constituency of the gassample line components. In FIG. 23 , a flow restrictor and differentialpressure transducer (206) is placed upstream of the sensor element andthe sampling pump. In FIG. 24 , the pump (212) is upstream of a flowsensing element (206) and the sensor element (210). The significance ofthis is that in FIG. 24 , the sensor element requires a leak-freeconnection at both ends. The benefit of this placement is that thesensor element, in certain configurations, namely packed bed columns,provides a pulse-dampening effect and flow laminarization from thesampling pump allowing a simple flow restrictor and differentialpressure transducer to effectively measure sampled gas flow rateswithout a flow laminarization device.

In FIG. 23 , the sensor element does not require a leak-free connectionon the downstream end, at the expense of the flow measurement device(206) requiring, in addition to a known resistance and differentialpressure sensor, a flow laminarization device. Component (216) is acamera for imaging the sensor response, as can be applied tocolorimetric packed-bed column reactors, but that component can be anysignal transducer appropriate to the applied sensor. Note that there arenumerous optical transducer approaches that apply to colorimetricpacked-bed columns, for example scanning reflectance measurements (suchas a barcode scanner or compact disk/DVD optical head) or bulkreflectance such as from a simple Light Emitting Diode (“LED”)excitation/Photodetector detection scheme. If a camera is used for(206), then a suitable lighting scheme (214) may be necessary. Anylighting scheme that provides even illumination may be suitable, butusage of LEDs as lighting elements is especially useful for manyreasons, not the least of which is the availability of numerouswavelengths. Appropriately selected illumination wavelengths can reducebackground noise in reflectance measurements and improve system signalto noise ratio. Component (218) illustrates a user interface, comprisedof a screen and interface buttons. Associated with (218) is a set ofelectronics and computational power capable of driving the userinterface and system components, as well as implementing variouscomputational algorithms and otherwise facilitating data processing.Component (208) illustrates an automated data uplink device, wherebymeasurement results, in electronic form, are automatically sent tolocations external to the breath analysis unit for implementation intodatabases, support groups, etc., as described elsewhere. Component (200)is a nosepiece, used to constrain user breathing into the device throughthe mouth and to also eliminate leakage of breath gases through thenose.

An illustrative implementation for obtaining information about aphysiological production rate of an endogenous volatile organic analytefrom a breath sample of a patient is as follows. First, an apparatus isprovided that comprises a breath input portion and an analysis portion.The breath sample is input into the breath input portion and directed tothe analysis portion. The breath sample is analyzed to sense the analyteand obtain the information about the physiological production rate ofthe analyte. A signal is generated in the apparatus that isrepresentative of this information. In some implementations, theendogenous volatile organic analyte is in near-zero concentration in theambient atmosphere and, preferably, in concentration ranges less than orequal to low ppm.

Taking advantage of the breath profile subject matter presented herein,in some implementations, the analysis of the breath comprises segmentingthe breath into a plurality of breath profile segments, wherein each ofthe breath profile segments corresponds to an anatomical region of thepatient that is non-identical to the anatomical regions for others ofthe segments. The breath profile segments are then analyzed to sense theanalyte within the anatomical region or regions corresponding to the atleast one breath profile segments to obtain the information about thephysiological production rate of the analyte. This approach, usingbreath profiles and anatomical segmentation, enables the most accuratemeasurement of production rate for volatile organic compounds, which islikely a superior analysis parameter than concentration alone.

Although the nature of some measurement phenomena is sensitive to thequantity of volatile organic compounds (moles of acetone, for instance)and not to the concentration in the sample per se, reporting of volatileorganic compounds measurements is almost universally in ppm. However,knowing the ppm of an analyte of interest in a given sample is not thesame as knowing the amount (in moles) of gas produced by the body in aparticular span of time. For many applications, the rate of volatileorganic compound production in an individual has greater utility thanknowing the concentration measured in a sample. There are many reasonsfor this, including the following.

Production time may not be the same as exhalation time. Although thevolume of breath in a single exhalation can be measured, the amount oftime associated with the production of the analyte in the breath samplemay not be accurately estimated (the amount of time associated with theproduction of analyte in the sample may and likely is not the same asthe duration of the breath exhalation.

Depending on the analyte, purpose of the test, and condition of thepatient, the concentration of the analyte in a single breath may not bethe same as the concentration of the analyte over a series of breaths.Furthermore, the concentration may vary significantly depending on theparticular breathing maneuver performed (see breath profile definition).

For the vast majority of use conditions, physiological steady-statecannot be assumed for a single breath, and thus the extrapolation ofsingle breath data into production rates is tenuous.

As such, a more useful metric of volatile organic compounds in breath ismoles per unit time (as compared to just moles). Further, this newmetric has particular utility when used in conjunction with our breathprofile embodiments and implementations.

Mathematical Model

The ensuing example uses acetone as the analyte. The analysis, however,can be broadened to various other analytes described herein.

If the partition coefficient at steady-state is known for an individual,then the concentration of acetone in the breath can be used toaccurately estimate the concentration of acetone in the blood under theparticular steady-state conditions. Furthermore, the rate of acetoneremoval from the body (through the breath) can be used to accuratelyestimate the rate of acetone production due to metabolic processes.

The following is an illustration of the application of mass balanceprinciples in the case of endogenously produced acetone. First, theamount of acetone produced per unit time (per minute in this example)needs to be measured. The amount of breath exhaled over a minute ismultiplied into the average concentration of acetone in the breathduring that time to yield the total acetone excretion:

$\begin{matrix}{{VAc} = {\frac{PV}{RT}{{Ve} \cdot {FeAc}}}} & \left( {{Eqn}.\mspace{14mu} 1} \right)\end{matrix}$

The variable VAc is the production rate of acetone per minute time, inmoles, Ve is the volume of breath exhaled per unit time with units ofliters per minute, and FeAc is the average fraction of acetone in theexhaled breath with units of liters of acetone per million liters ofbreath. The liters of acetone can be converted to moles using the IdealGas Law under the associated pressure and temperature (using n=PV/RT,where n is the moles of acetone, P is the pressure in kPa, V is thevolume in liters, R is the universal gas constant in units l-kPa/mol-K(with value 8.314 in these units), and T is the temperature in Kelvin atthe time of measurement).

A specific example of an apparatus that utilizes different profiles toanalyze different analytes is presented. The ensuing apparatus sensesoxygen, carbon dioxide, and acetone, which can provide a metabolismassessment.

Oxygen and carbon dioxide can be used to determine the respiratoryquotient (“RQ”), which is generally, the ratio of the carbon dioxideproduced to the oxygen consumed. The RQ varies from about 0.7 to 1.1.Among normal subjects, the RQ value is approximately 0.85. Those who areconsuming strictly carbohydrates have RQ values close to or about 1(assuming the intake is sufficient to meet the caloric needs of theindividual). When fats are predominately the source of energy, the RQapproaches 0.7.

Breath acetone, on the other hand, correlates to blood acetone, whichcorrelates to fat metabolism. However, the acetone concentration relatesto the magnitude of fat consumption in the individual, and as such hasbeen correlated to fat loss rate. The two measurands, though linked, donot provide the same information. Consider that RQ can be higher than0.85, for instance, while acetone levels are elevated, in individualsburning lots of fuel which is predominately carbohydrate. In this case,although most of the fuels consumed are carbohydrates, the individual isstill burning elevated amounts of fat. Thus, RQ and acetone combinedprovide significant information that neither provides alone.

In this embodiment, oxygen and carbon dioxide are measured usingrepeated non-rebreathing with tidal volumes. Acetone is measured viasingle-exhalation of the alveolar air.

An instrument that can measure both measurands in one sitting and thatcan sample for both using the analyte-specific optimal breath profilewill offer considerable analytical information that is not currentlyavailable using commercially available instruments or techniques.

A method and instrument for sampling and measuring RQ and acetone inhuman breath is shown in FIG. 16 . A breath profile for optimal samplingof the two measurands is shown in FIG. 9 .

FIG. 15 depicts a system comprised of: a three-way non-rebreathingvalve; a section of breathing hose; an automatic 3-way valve; a sensorblock containing sensors and fixtures for O₂, carbon dioxide, acetone,relative humidity, ambient pressure, and temperature sensors; and apneumotachometer.

In certain apparatuses, heating of the sensor block enables the sensorsto operate more reliably, both from the perspective of protection frombreath condensation and from the perspective of eliminated temperatureeffects on sensor performance. Two 5 watt silicone PSA heaters aresufficient to keep a block of aluminum (3.5″×2″×2″) at 38° C. usingeither commercial temperature controllers or simple analog setpointcircuits. Likewise, heating of the pneumotachometer screens (aLilly-style pneumotachometer was used in the development described here)provides resistance to breath condensation buildup and thus alterationof the pressure vs. flow rate waveform.

In this embodiment, the apparatus first measures the RQ and thenmeasures the acetone concentration. RQ is measured first since itsoptimal breath profile is a set of tidal volume breaths for an extendedperiod of time. This type of breathing is in fact the same as normalbreathing inasmuch as the sampling equipment does not impose a greaterburden on the user. The RQ measurement thus does not affect downstreammeasurements. After the RQ measurement is complete, the user isinstructed to exhale normally (perhaps with a visual or audio indicatorfrom the device) and then to wait for a given period of time. After theset time (again as perhaps indicated with a visual or audio cue), theuser is instructed to exhale the air from the deeper portions of thelungs as much as is possible.

Once the final exhalation is complete (sensed by the apparatus using adevice like a pneumotachometer), the three-way valve is closed. The“closed” 3-way valve allows the user to continue to breathe through theinstrument's non-rebreathing valve, but the exhaled breath is thendirected to exhaust directly outside the instrument while the instrumentproceeds with and finalizes the acetone analysis on the deep exhalation.With the three-way valve, the user does not need to disconnect from thedevice and it is not possible to contaminate the breath sample with more(upper airway diluted) gases. With the three-way valve, breathing afterthe acetone sample can allow the user to recover in preparation foranother breath test, as necessary.

In making ergonomic assessments (which will be specific for a particularapplication), one consideration is the dilutive effect of the design.Computing the amount of residual volume in the pneumatic system is afactor to consider. For instance, if using a 24″ length, 22 mm diametertube, the system will include approximately 200 ml of residual gas.Assume that the instrument is intended to measure an analyte in alveolarair space. Once the initial (approximately) 500 ml of “dead-air” spaceis evacuated, to sample the alveolar air, 200 ml will be required toforce the sample through. This 200 ml may be critical if the patient isonly able to exhale 250 ml of alveolar air (e.g., a young child or anelderly patient with COPD). Another approach would be to allow externalair to “push” any residual gas from the tubing. Such considerationsshould be adequately addressed in the design.

The patient's breath, in its entirety, may pass through the breath inputor the breath may be side-sampled, e.g., a fraction of the breath isanalyzed.

Depending on the sensors used, especially for low-level volatile organiccompounds, sidestream sampling may be beneficial. In this case, smallbore tubing can be attached to hose taps through the side of the sensorblock and miniature sampling pumps can withdraw samples through anyrequisite conditioning stages and into the volatile organic compoundsensor space.

The pneumotachometer, in the configuration described, is beneficial forboth attenuating mass transfer via diffusion at the outlet of the sensorblock (and, thus, no exit valve is required) and also for measuring thevolume of air breathed through the sensor setup. Note that the pressurewaveforms created by breathing through the pneumotachometer occur onlyon subject exhalations (and, only then when the 3-way valve is settowards the sensor block). Still, the pneumotachometer is capable ofseeing when the user exhales, including when the user has finished adeep lung exhalation. This sight enables the system to smartly deal withquality control issues and to provide data for useful feedback duringsystem operation (including measuring the breath rate of the individual,the tidal volume, and the total volume of breath in a sample or seriesof samples).

Advantages of this system include: optimal analyte sampling; appropriateanalyte sampling sequencing (it would be less appropriate to sample RQafter the acetone exhalation, since the acetone exhalation isconsiderably more physiologically perturbing); low breath resistance(pressure drops occur only over the non-rebreathing valve, thelarge-bore tubing, the large-bore sensor block, and the low-resistancepneumotachometer), specifically there is no need for an antibacterialfilter stage; and the ability to cascade longer and more complex breathsampling routines since the 3-way valve enables subject recovery afterdeep exhalations without removing the breathing valve.

Alternate embodiments are shown in FIG. 17 , FIG. 18 , and FIG. 19 . Theembodiment shown in FIG. 18 can be further described by FIG. 20 , FIG.21 , and FIG. 22 .

A variety of breath inputs may be used. When designing the instrumentfor the specific application of interest, it is desirable to account forcertain ergonomics. For instance, many patients find it uncomfortable tobreathe through devices with a high level of flow restriction. This isparticularly significant for young users, elderly users, and individualswith pulmonary disorders. However, also, if the patient is breathingmultiple breaths into a device, it may be uncomfortable for the patientto be manually holding the device for extended (e.g., 3-10 minutes) oftime. To account for this, certain ergonomic additions (e.g., a strap toattach the device to the face) may be employed. The device may also bedesigned as a portable bench-top system, where the user may sit next tothe device and breathe through a hose for the extended period of time.

FIG. 50 is an exemplary flow chart of the user-device interaction forone embodiment of a breath analysis system as disclosed herein. In thefirst step 8400 in the user-device interaction for one embodiment of abreath analysis system, a user inserts a cartridge (e.g., a testcartridge, as is described elsewhere herein) into the device. In someembodiments, the cartridge is inserted by the user until the cartridgereaches a mechanical stop position. For example, the user may insert thecartridge to a first position where part of the cartridge remainsoutside of the device. Alternatively, the user may insert the cartridgeto be fully inside the device as the first position. In otherembodiments, the user inserts the cartridge only a small portion afterwhich the device automatically accepts the cartridge to the correctdepth (the device may have any of a number of sensors to determine howdeep the cartridge should be inserted, including, but not limited to, aclick-type sensor, a photo sensor, a displacement sensor, or a processorthat communicates with a chip in the cartridge).

After insertion of the cartridge, in step 8405, the user begins toexhale into the mouthpiece of the cartridge. In one embodiment, the useris prompted to begin exhaling by the device. In another embodiment, theuser is not prompted to begin exhaling and merely begins exhalingwhenever the user is ready. In either embodiment, the device may includea sensor to detect the beginning of the user's exhalation. The sensormay be a flow sensor, pressure sensor, or other sensor described below.In some embodiments, the user may be notified that the device has sensedthe beginning of the breath sample by an LED, or other audio/visual orhaptic indication. Next, in step 8410, the device obtains an alveolarbreath sample. In step 8415, the device directs a first portion of thebreath sample that the user is exhaling to a first flow path. The firstflow path may be in the device or in the cartridge. This portion of thebreath most likely does not contain any alveolar breath as it includesmostly breath from the mouth. After this step, the user receives anotification to continue exhaling in step 8240. The notification in step8420 may coincide with step 8425 where the device directs a secondportion of the breath sample to a second flow path. The second flow pathis in the cartridge. The second portion of the breath preferablyincludes alveolar breath from the lungs. Step 8420 may also occurimmediately after step 8425. When this transition from the first flowpart to second flow path occurs, the user may notice a change in theresistance to the user's breath or in the flow of the breath. Thenotification to the user to keep exhaling may prevent the user from stopbreathing when the transition occurs. The notification may also assurethe user that the device is operating correctly. This notification maybe audio, visual and/or haptic and any combination of these. In oneembodiment, the device is monitoring the flow of breath being exhaledinto the device by means discussed elsewhere in this specification. Ifthe device determines that the user has stopped exhaling at any pointprior to the device obtaining an alveolar sample, the user will get anindication that the device has abandoned the test as shown in step 8430.The indication may be audio, visual or haptic or some combination. Ifthe device successfully obtains an alveolar breath sample, the deviceinforms the user by audio, visual and/or haptic feedback that the usermay stop breathing into the cartridge or device as shown in step 8435.In one embodiment, the next step is step 8440, and the user pushes thecartridge into a second position inside the device for the analysis tobegin. In one embodiment, the device prompts the user to push thecartridge into a second mechanical position in the device as in step8440. In another embodiment, the device may begin the processing of thebreath sample without further intervention by the user. In eitherembodiment, in step 8445, the device outputs the result of its analysisof the breath sample. The output of the device may be audio or visual orthe device may communicate the output to another device, such as asmartphone or tablet.

FIGS. 51A-B show exemplary cartridge designs identifying features andvariables that can be optimized for certain applications described inthis disclosure. For certain applications, it may be desirable for auser to be able to exhale directly into a cartridge. This type of designmay eliminate the need for a breath bag and/or a pump. If not pump orbreath bag is used, then the cartridge will be configured to operatewith pressure generated by the human respiratory system.

Expiratory pressure varies based on a user's sex, age, smoking statusand other variables, such as whether the individual has asthma, COPD orother respiratory conditions. Typically, expiratory pressure isdetermined empirically using spirometry. General ranges of maximumexpiratory pressure (MEP or PEmax) are provided in the below chart(Wilson 1984):

TABLE 2 Significance of the sex differences in mean maximum respiratorypressures in adults and in children (values are means with standarddeviation in parentheses) Group (n) Age (y) Height (cm) Weight (kg)PE_(max) (cm H₂O) PI_(max) (cm H₂O) Men (48) 34.7 (14)  179 (6)  74.5(8.5) 148 (34)  106 (31)  Women (87) 36.8 (13)  163 (7)  61.4 (9)   93(17) 73 (22) Significance of t NS p < 0.01 p < 0.01 p < 0.001 p < 0.001Boys (137) 11.1 (2.2) 149 (15)  41 (12) 96 (23) 75 (23) Girls (98) 11.6(2.5) 147 (16) 40.5 (12)  80 (21) 63 (21) Significance of t NS NS NS p <0.001 p < 0.001

Using the equations in the above chart, the predicted maximalrespiratory pressure in adults and children can be estimated (Wilson1984):

TABLE 3 Prediction equations for maximal respiratory pressures in adults(over 18 years) and children (7-17 years) Group PI_(max) (cm H₂O)PE_(max) (cm H₂O) Men  142 − (1.03 × Age*) 180 − (0.9 × Age*) Women−43 + (0.71 × Ht†)  3.5 + (0.35 × Ht†) Boys 44.5 + (0.75 × Wt‡)  35 +(5.5 × Age*) Girls   40 + (0.57 × Wt‡)  24 + (4.8 × Age*) *Age in years.†Height in centimetres. ‡Weight in kilograms.Other reports show slightly lower ranges. In one study, men generate MEPfrom 62 to 97 cmH₂O and women generate levels from 38 to 62 cmH₂O. Thesame study shows an age dependence with a decrease in MEP in men from106 to 68 cmH₂O between the ages of 20 to 60 and a decrease in womenfrom 65 to 49 cmH₂O between the same ages.

As such, if a device is to have broad applicability across children,adult men and elderly women, the device should support expiratorypressures as low as 40 cmH₂O (=29.4 mmHg or 0.569 psi) and this assumesthat all users are capable of and chose to exhale at their MEP for theduration of a measurement cycle.

If the device is designed primarily for healthy adults, such as foradult athletes, a higher expiratory pressure may be supported. Forexample, an expiratory pressure of 90 cmH₂O may be used.

Instead of evaluating this from the perspective of human capability,another way of evaluating the desired flow resistance of a cartridge arethe flow requirements to obtain a measurable colorimetric signal. In thecase of breath acetone in a cartridge, such as the one described in FIG.51A, it is desirable that 400 ml of breath at 3 ppm be directed throughthe cartridge over a period of 10 seconds. These characteristics imposea certain maximum flow resistance that can be contained within thecartridge.

Variables Involved in Cartridge Flow Resistance

In view of the foregoing, it is desirable that the cartridge flowresistance be optimized such that the desired user can exhale throughit.

FIG. 51A shows a cross section of a cartridge 8700. The cartridge 8700has two outer walls 8500. Within the cartridge 8700, an inner wall 8510creates a gap that defines Flow Path B on one side and Flow Path A onthe other side. In this embodiment, Flow Paths A and B are used by theuser to exhale directly into the cartridge 8700. In such an embodiment,a pump or breath bag may not be required. In another embodiment, FlowPath B is configured to be part of the device and is outside thecartridge 8700 while Flow Path A remains in the cartridge 8700. Intheory, these two flow paths will share the total flow as parallel orshunted flow paths according to principles known in the field of fluidmechanics. The ratio of their resistances will enable one to predict therespective flow rates through them. Similarly, one may set or adjust therespective resistances of the flow paths to achieve a desired relativeflow through them. The setting of this ratio may be guided by ordetermined from various factors, e.g., such as patient or userdemographics (e.g., age, sex, etc.), by physiological state (e.g.,smoker, non-smoker, hyperventilating, etc.), and so on. In thisillustrative embodiment, the flow resistance in Flow Path B isessentially zero and the resistance in Flow Path A is sufficiently highthat the flow is directed through Flow Path B. This continues until asolenoid blocks Flow Path B, thus forcing the user to exhale throughFlow Path A.

In FIG. 51A, Flow Path B is an unobstructed, separate flow path fromFlow Path A. In another embodiment, as shown in FIG. 51B, Flow Path Bcould be an opening or openings 8505 on the side or sides of Flow PathA. Other arrangements could also be used with other embodiments.

With regards to both FIGS. 51 A and B, Flow Path A includes a lower disk8515, a bed of desiccant 8525, a middle disk 8530, the bed of reactivebeads 8535, and an upper disk 8550. The low disk 8515 may be a porouspolyethylene disk with a thickness of X1. The bed of desiccant beadsincludes beads 8525 with a diameter of X2. The desiccant chamber widthis X3 and height is X4. X5 is the void factor in the reactive chamberand is defined as the void volume divided by the total volume. Themiddle disk 8530 may be a porous polyethylene disk with a thickness ofX6 with a disk porosity of X7. The reactive beads 8535 have a diameterof X8. The reactive bead chamber width is X9 and height is X10. Thereactive bead chamber may also include a void 8540. And, the reactivechamber may include an upper disk 8550. All of these structures withtheir various dimensions will impact the flow resistance.

For example, an increase in the thickness of the lower disk, X1, willincrease the flow resistance of Flow Path A. A decrease in the X1 willlower the mechanical rigidity of the lower disk on the other hand. Ifthe lower disk is too thin, then particles may not be properly containedin the lower disk area 8520. A thin lower disk will also be harder tomanage in an assembly process. As the size of the pores of the lowerdisk increases, the flow resistance decreases. As the pore size of thedisk increases, the diameter of the beads that can be contained by thedisk has to increase. This decreases the surface area available forreaction. The same will be true for the middle disk and the upper disk.

The porosity of the permeable, or porous discs (as discussed herein)which maintain the support beads within the reaction chamber and theflow rate permitted through the support beads may be configured toenable a flow rate of breath of at least about 100 cc's and in someimplementations at least about 200 cc's or 300 cc's or more in no morethan about 2 minutes and optimally no more than about 120 seconds or 60seconds or less, under a reference pressure of 1 psi. That referencepressure is within the range of pressures that can normally be generatedexhaling from a healthy lung, which exhaling pressure may be as high as2 psi in a healthy adult. This enables the test to be run directly onexhaled volume of breath, without the need for a breath container suchas an inflatable bag, and without the need for a pump to generate enoughpressure to drive the sample through the analytical pathway.

The flow rate can also be adjusted by adjusting the total support volumerelative to the reaction chamber volume. Total support volume representsthe smallest volume that the support will occupy when snugly packed butwithout deformation of the support structures. Thus, for example, wherethe support comprises beads, the total support volume equals the sum ofthe volumes of the individual beads plus the total volume ofinterstitial spaces in between the beads. Total support volumes ofbetween about 10% and about 70%, and in some implementations betweenabout 20% and about 50% of the reaction chamber volume may be desirable.Low packing volumes such as on the order of 20% or 10% or less of thereaction chamber volume, depending upon bead size, may allow beads topack tightly against the effluent filter and increase the pressurerequired to maintain a desired flow rate.

In any of the foregoing constructs, it may be desirable to provide awick for facilitating the flow of liquid from the ampoule to the beads.The wick can comprise any of a variety of surface structures forfacilitating liquid flow, such as a porous strip of a material such aspolyethylene or other material having suitable stability in the intendeduse environment. Further embodiments including wicks are discussedelsewhere herein.

An increase in the desiccant particle diameter, X2, will decrease theflow resistance of Flow Path A as long as the number of desiccantparticles is reduced over all. An increase in the desiccant particlediameter will also decrease the surface area that is available to drythe breath sample. The desiccant may be unnecessary altogether if thechemistry is not moisture-sensitive (e.g., color is not attenuated inthe presence of water) or if the intended use expects very highconcentrations of the analyte of interest such that any attenuation isnot expected to impact efficacy. The same is generally true for thereactive bead diameter, X8.

In addition, increasing the desiccant chamber width, X3, increases thechamber size which should decrease the flow resistance. Of course, thisassumes that there is not a proportional increase in the number ofdesiccant particles. Similarly, increasing the desiccant chamber height,X4, will also increase the chamber size and decrease the flowresistance. As with the desiccant chamber width, X3, a proportionalincrease in desiccant particles could nullify any increase in chamberheight. So, if a larger chamber is packed with a certain % of beads, thebenefit of the larger chamber dimensions may be overtaken by theincreased overall flow restriction from the beads. The same is true forthe reactive bead chamber width, X9, and reactive bead chamber height,X10.

Also, if the void factor, X5 increases, the flow resistance willdecrease. However, as the number of desiccant beads decreases, thesurface area available for the reaction also decreases.

One of skill in the art could evaluate different cartridgeconfigurations by considering the following relationships. Generally,the resistance through a tube is given by:

$v = \frac{Q}{A}$where v is the velocity, Q is the flow rate, and A is the crosssectional area of the tube. Furthermore, Q can be defined as

$Q = \frac{P_{2} - P_{1}}{R}$where Q is the flow rate, P is the pressure at one of two points (1, 2)and R is the flow resistance. R can be defined by the followingrelationship

$R \propto \frac{n \cdot L}{r^{4}}$where R is the flow resistance, n is a set of physical propertiespertaining to the fluid, L is the length of the column and r is theradium of the column. Of course, hydraulic radii may be used ifapplicable and appropriate.

For packed beds, the Kozeny-Carman relationship may be used.

$\frac{\Delta\; P}{L} = {\frac{180 \cdot \mu}{\phi_{s}^{2} \cdot D_{p}^{2}} \cdot \frac{\left( {1 - ɛ} \right)^{2}}{ɛ} \cdot v_{s}}$where viscosity, sphericity of the beads, particle diameter and voidfactor are all considered. This version of the equation only applies tolaminar flow.

One cartridge embodiment that may be useful for applications such asmonitoring adherence to ketogenic diets involves the followingparameters. Using a cartridge with an internal diameter of approximately0.7 cm, disks that are 1/48″ are used (50 to 90-micron pore size).Approximately 5 mg of reactive silica beads (140-170 mesh) are used in areactive chamber that is 30% full. Approximately 190 mg of calciumchloride beads (12-18 mesh) are used in a loosely packed chamber. One ofskill in the art would be able to use the foregoing relationships andexamples to determine other dimensions for use in embodiments.

FIG. 53 , FIG. 54 , FIG. 55 and FIG. 56 show embodiments of a breathanalysis system that is configured to generate a rapid response usingalveolar breath. Like other breath analysis systems described herein,the system is comprised of a device 8705 and a disposable cartridge8700. This embodiment may operate without a breath bag or breathcontainer. It further may operate without a pump, at least in the mostbasic configurations. However, in certain embodiments, a pump may beused. In other embodiments, a breath bag or breath container can beused.

FIG. 53 shows a view of the device 8701 with a lower housing 8715 andupper housing 8705 with a cartridge 8700 inserted. The device mayinclude a display 8710. The display 8710 may include a touch screen. Thedevice 8705 may be rectangular with side wall 8715 and a back 8720.

FIG. 54 shows a cross sectional side-view of the cartridge 8700 and atop view of the cartridge 8700. In the side-view, the cartridge includesan inlet 8800, with a mouthpiece 8805, a reactant bead chamber 8810 withreactive beads 8815, an ampule 8825 including a chemical reactant 8820,and a wick 8830 with a lower portion 8840, a middle and an upper portion8835. The cartridge 8700 also includes a hammer access opening 8828which allows a hammer to contact the ampule as discussed elsewhere inthe specification. A viewing window 8855 is arranged next to thereactive bead chamber 8810 to allow a color sensor 8850 on the device tosense the color in the reactive bead. An LED 8845 may illuminate thetreated material through the window 8855.

In the top view in FIG. 54 the cartridge 8700 is shown along the dashedline from the side-view. The cartridge includes Flow Path A whichincludes a lower disk 8860, a bed of desiccant 8800, a middle disk 8865,the bed of reactive beads 8815, an upper disk 8870, and an ampule 8825.Flow Path A has an inlet 8885 and wall 8805 and outlet 8895. Flow Path Bincludes 8890 and outlet 8898.

FIG. 55 shows the insides of the device 8701 with an inserted cartridge8700. The device 8701 includes a hammer 8905, a first mass flow sensor8910, an outlet flow path 8945, a second mass flow sensor 8935, asolenoid valve 8930, a display 8710, a microprocessor 8925, a USB port8920, a color sensor 8940, and an LED light 8941.

FIG. 56 shows a cross sectional side view of the device 8701 with aninserted cartridge 8700. The hammer 8905 of the device 8701 is mountedon a pivot point 9010. The hammer 8905 is positioned so that its head isdirectly above a hammer access opening 8825. A hammer sled 9000 keepsthe cartridge 8700 from moving laterally and acts as a first mechanicalstop as the cartridge 8700 is inserted into the device 8701. As thecartridge is further inserted with some force 9040 such as a thumb, thehammer sled 9000 moves further into the device 8701 until a second stopis reached in the divide 8701. At that point, the hammer 8905 is pivoteddown by its contact with a ledge, forcing the hammer 8905 to piece thecrushable glass ampule 8825. A rubber band wrap 9035 surrounds theampoule.

This system is described in terms of the steps described in FIG. 86 :(a) directing alveolar breath to the reactive chamber, (b) releasing theliquid, (c) wicking the liquid through the reactive chamber, (d)detecting color via a color sensor and (e) displaying the output.

Starting the Test

With respect to FIG. 52 , a first step 8600 may be to instruct the userto exhale into the cartridge or device. The device may instruct the userto exhale into the cartridge by means of an audio, visual and/or hapticindication. A visual screen 8710, for example, may be part of the device8705. Alternatively, as in step 8601, the user may indicate to thedevice that breath exhalation has begun. The user may indicate the onsetof exhalation by various means to the device, such as by pressing abutton, voice recognition, etc. The mechanism for the device todetermine the start of the breath input may incorporate one or more of apush button, a pressure sensor, a flow sensor, humidity sensor,temperature, and a photodiode. In one embodiment, the user may depress aphysical button close to the time in which the user will start to breathinto the cartridge and/or device. If the button is pressed again it maybe assumed that the first press was in error and the second presssignals the true start of the breath input. In another embodiment, thebutton is on a touch screen of the device or on a mobile devicewirelessly connected to the device to controlling the device.

In another embodiment, in step 8602, the deep lung system may determinethat the user has begun to exhale. In one embodiment, the deviceincludes a photodiode near the mouth piece. When the user places theuse's mouth on the mouth piece (in preparation to exhale), the user'smouth will cover the photodiode. Accordingly, the ambient lightingconditions will become dark (because it is in the user's mouth) and thephotodiode can detect the lighting change. Once the photodiode detectsthat it is in a dark environment, it outputs a signal that can indicatethe start of the breath input. In another embodiment, similar to theprevious, the deep lung feature may incorporate a humidity ortemperature sensor to augment or replace the photodiode. The human mouthis typically more humid and hot that the ambient environment. Thus, ahumidity or temperature sensor may also be able to determine that theuser has placed their mouth on the mouth piece and signal the start ofthe breath input. In another embodiment, the deep lung feature mayincorporate some form of a flow sensor. When the user begins to exhale,the flow sensor detects the flow of air and signals the start of thebreath input. A flow sensor may operate by including a turbine that isattached to an electrical generator. When the turbine spins it generatesan electric current which indicates air flow. In another embodiment, thedeep lung feature may incorporate some form of a pressure sensor. Whenthe user begins to exhale they will exert a certain amount of pressurewhich the pressure sensor detects and signals the start of the breathinput. The pressure sensor may operate by including a piezoelectricmaterial which experiences a change in its resistivity once pressure isapplied.

Directing Alveolar Breath to the Reaction Chamber

In the next step 8605, the device or cartridge or both together, directthe alveolar breath sample to the reactive chamber of the cartridge. Inone embodiment, the user exhales through the mouthpiece 8805 of acartridge 8700. The cartridge contains two flow paths, Flow Path A andFlow Path B. Flow Path A leads to various chambers in the cartridge.Flow Path B can be the route instead of Flow Path A for a breath samplethat does not contain alveolar breath. Flow Path B thus serves to routethe breath sample out of the cartridge. In one embodiment, Flow Path Bmay be a separate flow channel from Flow Path A. In another embodiment,Flow Path B may be a detour from Flow Path A. In either design, bydefault, the breath sample travels the path of least resistance, whichis initially Flow Path B.

Flow Path B directs the breath sample from the inlet 8890 to the exit8898. When the cartridge 8700 is inserted into the base unit 8720, anairtight seal is made between the exit 8898 of Flow Path B and a path(8945) to a solenoid valve 8930 that is in the open position when theuser first exhales. As the breath sample traverses this flow path, itpasses by a mass flow sensor 8935 before it is discarded to the outsideenvironment. The breath will continue to take this detour until theprocessor (8925) instructs the solenoid valve to switch to a closedposition. With the valve closed, the path of least resistance willbecome Flow Path A. At this point, a user's breath should containalveolar breath. As such, the device directs alveolar breath to thereactive chamber in step 8605 by the switch of the flow path from FlowPath B to Flow Path A.

Flow Path A directs the breath sample from the inlet 8885 through adesiccant chamber 8880, a reactive chamber 8815, a liquid developerchamber 8825 and an exit 8895. As the breath exits the cartridge, ittravels past a second mass flow sensor 8910, and then out of the device,back to the outside environment.

The form factor of the base unit is not intended to be limiting. Forexample, the base unit may be substantially smaller than the base unitsshown in the figures, but it may still work with the same disposablecomponents. In some embodiments, the base unit is portable, such as lessthan about 250 cubic inches, or less than about 125 cubic inches (or 5inches cubed). In other embodiments, the base unit is between 27 and 125cubic inches. For example, in at least one embodiment, the base unit isapproximately 27 cubic inches (3 inches cubed). In other embodiments,the base unit is between 8 cubic inches and 27 cubic inches. Forexample, in at least one embodiment, the base unit is approximately 8cubic inches (2 inches cubed). In other yet embodiments, the base unitis less than 8 cubic inches. Of course, the cuboidal shape is notlimiting, e.g., the base unit may be other shapes.

In some embodiments, the cartridge is compact. For example, thecartridge may be less than about 8 cm in length. In other embodiments,the cartridge is less than about 6 cm in length. For example, in someembodiments, the cartridge is about 5.3 cm, including the length of thehandle. In other embodiments, the cartridge is between about 4 cm and 6cm. In certain configurations, the cartridge is less than 4 cm. Thewidth of the cartridge is typically no more than about 33% of theheight, and often is no more than about 20 to 25% of the height.

In some embodiments, the height of the reactive chamber of the cartridgeis short. In certain embodiments, it is less than about 3 cm. In certainembodiments, it is less than about 2 cm. In other embodiments, it isless than about 1 cm. In still other embodiments, it is less than 0.5 cmor between 0.25 cm and 0.5 cm. In other embodiments, it is less than0.25 cm. The ratio of the height of the reactive column to the height ofthe column overall is often less than 25% and is preferably less than10%.

In some embodiments, the breath bag volume is less than about 1 L. Incertain embodiments, it is between about 500 ml and 1 L. In otherembodiments, it is between about 250 ml and 500 ml.

The system may include a fractionator or venting system to determine howmuch breath has passed through a give part of the system. Any of thenumber of fractionators and/or venting systems discussed herein may beused, including user-initiated, device initiated (automatic),mechanical, or sensor-based based fractionators.

Releasing the Liquid

In this embodiment, after the user's breath has been run through thesystem, the disposable cartridge is activated and the reactive material8815 is saturated with a developer solution. The solution is stored in asealed ampoule 8825 made from crushable glass. It may be resistant toultraviolet (“UV”) light (or covered by a UV light shield) and is in theshape of a cylinder with spherical ends. It is approximately 1.5″ longand 0.25″ in diameter. When the ampoule is broken open by the actuationmechanism, the solution floods the cartridge cavity that the ampoule8825 is housed inside.

In this embodiment, the actuation mechanism is comprised of thefollowing components: glass crush hammer 8905, hammer sled, crushableglass ampoule, developer solution, and microprocessor. They worktogether to release and distribute developer solution in a controlledway that ensures full saturation of the reactive material. When the useris prompted by the microprocessor to push the cartridge into the deviceas far as it will travel, the ampoule is broken open by the hammer whichis made of rigid plastic or metal. This hammer is on a pivot and ispivoted downward onto the ampoule by interference with other plasticfeatures on the inside of the base unit housing as the sled moves deeperinto the base unit. A torsion or coil spring returns the hammer to itsoriginal position when the cartridge sled is restored to its originalposition and the cartridge is removed. In this embodiment, the hammer isattached to the sled at the pivot point. The hammer tip is designed tohave very little surface area which increases the force applied to theampoule during actuation. The cartridge has mating features thatinterlock with the sled and the two become one as the cartridge dragsthe sled along to a new, deeper position inside the base unit. Thecylindrical glass ampoule is supported by features inside the cartridgethat promote breakage. One support at each end of the ampoule's lengthso that the hammer applies force directly in between the two supports.The shards of crushable glass stay inside the cartridge and do not comein direct contact with the user. An elastomeric membrane covers theopening in the cartridge that the hammer tip travels through. The hammernever punctures the membrane that flexes and takes on the temporaryshape of the hammer tip. This keeps glass shards and liquid solutioninside the cartridge. For this embodiment, the membrane can be installedas a wide rubber band that wraps around an entire end of the cartridgeand covers the hammer tip opening. This opaque, wide rubber band alsoserves as a UV light shield for the sensitive developer solutioncontained inside the glass ampoule. The glass ampoule is either an amberglass or a near opaque glass.

Wicking Liquid Through the Reactive Chamber

Referring to the same embodiment, within the ampoule cavity is a stripof wicking material 8830 that is comprised of an optional portion thatis within the ampoule cavity 8835 and a portion that is within thereactive bead cavity 8855. The wick runs the entire length of theampoule and continues on into the neighboring reactive chamber where itcomes into direct contact with the reactive material (loosely packedsilica beads). In this instance, the wick strip is comprised of aporous, hydrophilic polyethylene material and it is approximately 2″long by 0.25″ wide, by 0.0625″ thick, but other materials and sizes canbe used as well including those described herein. The solution is wickedfrom one cavity to the other until the reactive material is fullysaturated.

Detecting Color Using a Color Sensor

A color is formed when the reactive material interacts with a developersolution. One of the reactive chamber walls serves as a viewing windowto the exterior of the cartridge. This window is transparent and gives afull view of the reactive material. In FIGS. 63A-C, a different designis shown in which the reactive chamber is viewed perpendicular (insteadof parallel) to the initial flow direction of the breath sample. Ineither case, when the cartridge is inserted into the base unit, thecartridge is lined up in such as a way that the viewing window is indirect view of an optical sensor.

In certain embodiments the system incorporates a sensor which exhibits aphenomenological color change. For example, depending on theconcentration of an analyte in a gas sample, the sensor may induce acolor change between light blue and dark blue. In such embodiments, thesystem should incorporate some mechanism to capture this color. Themechanism to capture the color may incorporate one or more of aphotodiode, color sensor, image sensor, lens, light filter, illuminationsource, and light pipes.

In one embodiment the system incorporates an LED illumination sourcethat emits a light with a phenomenologically specific wavelength toinduce a desired spectral response. The light from the LED is optionallydirected at a light pipe constructed from plastic or glass thatredirects the light to the region of color change. The light passesthrough the region of the color change such that the exiting orreflected light is a different color. The exiting light is optionallyrouted through a second light pipe for a sensing region. A photodiode ifpositioned such that the exit light that arrives at the sensing regionwill enter into the photodiode. The photodiode may optionally beequipped with a lens and a filter to focus the light and filter outphenomenologically irrelevant signals. The photodiode may be connectedto an analog to digital converter to convert the color response into adigital output. In some embodiments there may be multiple photo diodesand those photodiodes may contain different filters. For example, oneembodiment may call for three photodiodes specific to red, green, andblue light respectively.

FIG. 57 illustrates another embodiment that includes glass/quartz wool9105 for its chemistry. In FIG. 57 , a cartridge includes porous disks9100, desiccant 9150, glass/quartz wool 9105, a crushable glass ampoule9110, a hammer access opening 911 a hydrophobic permeable disk 9120, adetour pathway 9130, and a viewing window. The device into which thecartridge is inserted may include a color sensor 9140, and LED light9135 and a PCB 9125.

Color Sensing Algorithms

In certain embodiments the system incorporates a sensor which exhibits aphenomenological color change. For example, depending on theconcentration of an analyte in a gas sample, the sensor may induce acolor change from light blue to dark blue. A color sensing algorithm maybe used to quantify this color change. The color sensing algorithm mayincorporate one or more of the following pieces of information (1) ascalar or vector representation of the input color (2) a reference color(3) a calibration curve or lookup table.

In one embodiment, the sensing algorithm accepts a single scalar colorvalue. This color value is compared against the reference color todetermine a difference. This difference may involve one or more of asimple arithmetic subtraction, Euclidean distance of an RGB value, or acolor space distance computation. In the event that a color spacedistance is used, the specific algorithm may use a perceptual colordistance computation that mimics how humans perceive color differences,often called Delta E. An example of a perceptual color differenceequation is CIEDE2000 published in 2005 by Sharma et al. Once thecomparison value between the reference color and input color is known itis compared again a calibration curve or look up table to determine thecorresponding analyte concentration.

In another embodiment, the sensing algorithm accepts multiple colorvalues in the form of a pixel map or image representation. The sensingalgorithm may compute an average or some other aggregate metric on thesevalues. Or, alternatively, the sensing algorithm may use the multiplevalues to simply ensure that all values are sufficiently similar to oneanother indicating that an error likely did not take place.

In another embodiment, the sensing algorithm accepts multiple colorvalues but these color values may have been taken at different times.This is useful in cases in which not only is the color changephenomenologically significant, but the rate at which it changes issignificant as well. Additionally, this is useful in cases in which thetime needed for a full color change is not known and must be determineddynamically by the system by continually checking until the color stopschanging.

Orientation Check

In certain embodiments the system incorporates the use of a developersolution and an activation mechanism by which the developer solution isoperatively used. In such embodiments the system may further incorporatea tracking mechanism to track when, if, and how much of the developersolution has been used. The tracking mechanism will be primarily used todetermine that a reading was performed correctly and fully.

In one embodiment, the activation mechanism incorporates action onbehalf of the user in which they shake, rotate, or otherwise orient thedevice in a certain position which allows the developer solution to bedispensed. For example, the user may push a button to open a valve andthen rotate the device by about 90 degrees so that gravity may cause thedeveloper solution to pass through the valve and into a cartridge. Insuch an embodiment, the tracking mechanism may incorporate the use ofone or more of a magnetometer, accelerator, gyroscope, andmicroprocessor. Using these components, the tracking mechanism willdetermine that the device was in its “normal” position during theinitial phase of a reading (i.e., the developer solution was notreleased early) and then rotated between two threshold angles (forexample, 75 degrees and 105 degrees) for a certain amount of time (forexample, 10 seconds). Moreover, the tracking mechanism may ensure thatthe device is not violently shaken before activation in a manner thatruns the risk of the developer solution being released accidentally.Likewise, the tracking mechanism may ensure that the device is heldsteady and does not move during the time it is rotated.

In another embodiment, the activation mechanism is similar to theprevious embodiment, but the tracking mechanism may be augmented by orreplaced with a mechanism that incorporates a mass flow sensor in-linewith the cartridge and measures how much of the developer solution passinto the cartridge. The tracking mechanism ensures that no developersolution is dispensed until the appropriate time and then furtherensures that when the time comes, an appropriate amount of developersolution is dispensed in a certain time range.

In another embodiment, the activation mechanism is similar to theprevious embodiment, but the tracking mechanism may be augmented by orreplaced with a mechanism that incorporates a fluid volume sensor whichmeasures the amount of unused developer solution. The fluid volumesensor may incorporate one or more of a photodiode, camera, or otheroptical sensors to visually determine how much solution remains andensures that the developer solution is dispensed only at the appropriatetimes. Alternatively, the fluid volume sensor may incorporate the use ofelectrode to measure the resistance across the developer solution. Asthe developer solution is used the resistance across the developersolution changes and thus the device is able to determine that thedeveloper solution is dispensed appropriately.

In another embodiment, the activation mechanism is similar to theprevious embodiment, but the tracking mechanism may be augmented by orreplaced with a mechanism that incorporates one or more of an altimeter,pressure sensor, temperature sensor, and Global Positioning System(“GPS”) module as the tracking mechanism may need to operate differentlydepending on the environmental conditions. For example, if the ambientenvironment is very cold the device may need to be rotated and keptstill for a longer period of time.

In another embodiment, the activation mechanism is similar to theprevious embodiment, but does not require explicit user input. Forexample, instead of the user pressing a button to open a valve, thevalve is programmatically opened by microprocessor based on input fromthe tracking mechanism. For example, the tracking mechanism mayincorporate an accelerometer and when the accelerometer determines thatthe device is being shaken it causes the microprocessor to automaticallyopen the valve.

FIG. 65A shows another embodiment of a breath analysis subsystem inwhich the time of breath sampling and the time of breath analysis may besubstantially different and are thus decoupled.

The embodiment is comprised of a base unit 10005, a cartridge 10010, anintegrated mouthpiece 10015, and a mobile device 10020. The base unit10005 is comprised of a color sensor (not shown in FIG. 65A), adetachable liquid container 10030, a ROM chip reader, and a cartridgeinsertion port 10025. The cartridge insertion port is configured toreceive a cartridge 10010. When the cartridge is inserted, it can movebidirectionally, although the primary output is on the backside of theunit shown in FIG. 65B (implying that, at least for a 7-day cartridge, apreferred direction of movement is “through” the device and out theother end).

The cartridge may contain a plurality of test chambers as shown in FIG.66B or it may comprise a single test chamber as shown in FIG. 66A. Inthis design, the cartridge is comprised of three barriers 10520, 10525and 10530 that separate chemical reagents, such as desiccant andreactive beads. The cartridge also comprises an EEPROM chip, such as aread only memory chip or similar memory storage device 10210.

The integrated mouthpiece 10015 is comprised of a button 10105, an LEDindicator light (shown as block dot near button 10105), a samplecollection valve (not shown), a clock (not shown), and a cartridgereceiving port through which the cartridge may be inserted (as shown inFIGS. 65B-C).

In this system, cartridge is first inserted into the integratedmouthpiece and aligned with a specific test chamber within thecartridge. The user exhales through the mouthpiece at timing specifiedby the LED shown in FIG. 67 so that a breath sample is delivered to thetest chamber. At this time, the first two steps of the chemical reactiontake place: the sample is dried by the desiccant and it is also reactedwith the reactive beads. The cartridge is then inserted into the baseunit. The base unit analyzes each test chamber individual using asensor. The sensor generates a raw signal, which is computed andprocessed to create a result. The result is transmitted wirelessly fromthe base unit, such as to the user's mobile device or directly to aremote server.

In the above embodiment, the base unit serves as the primary mode ofanalysis, as it is comprised of the processing mechanism, in this case acolor sensor. Upon insertion of a cartridge, the base unit providesbidirectional movement of the cartridge in order to read the ROM chip,as well as analyze individual test chambers within a cartridge. The baseunit also comprises a developer solution container. This container isoptimized to require replacement at a less frequent rate than thecartridge use. Ideally, this container would hold enough developersolution for roughly 100 tests, and would be able to dispense enoughsolution to react with an additional reactant or chemistry, and create areaction product, or response. A useful range of developer solutionwould be approximately 100 microliters. In another embodiment, it isbetween about 60-100 microliters. In another embodiment, it is betweenabout 40-60 microliters. In another embodiment, it is between about20-40 microliters. In another embodiment, it is between about 10-20microliters.

In the above embodiment, the integrated mouthpiece serves two purposes.First, the mouthpiece acts as a trainer, and assists the user increating a desirable breath profile. U.S. Patent Application No.62/247,778 describes different profiles and is incorporated by referenceherein. As an example, the LEDs on the mouthpiece may instruct the userto begin to exhale into the room when the LED is green and then throughthe mouthpiece when the LED is red and to stop when the LED is blue. Themouthpiece may also block flow paths using a solenoid as describedelsewhere in this disclosure.

Second, the mouthpiece comprises a clock or time-stamping mechanism. Asan example, this mechanism can place a time stamp on each individualtest chamber within the cartridge. In one application of this system,the user would collect samples every day for a week. The cartridge wouldcontain only one test chamber for one breath sample. The cartridge wouldbe inserted into the base unit every day for analysis. The base unitwould analyze only one test chamber on a daily basis. In anotherapplication of the system, the cartridge would be comprised of multipletest chambers. In this example, the base unit comprises a mechanism forbidirectional movement, which allows the base unit to ignore previouslyanalyzed chambers and move onto the test chamber collected on thatspecific day. In another application of the subsystem, the user may usermultiple test chambers over the course of a day. The base unit wouldrecognize the time stamps that were assigned to each cartridge testchamber by the integrated mouthpiece.

The cartridge can be comprised of either one or multiple test chambers.The multi-chambered cartridge can utilize both multiple tests using asingle analyte, as well as multiple test using multiple analytes. Eachtest chamber is comprised of small quantities of reactant.

The inventors have learned that small quantities of desiccant can beused when the flow characteristics and geometries of the system areoptimized. As an example, calcium chloride readily absorbs moisture, andcan be placed into a loosely-packed bed of roughly 5 or 6 granules,amounting to substantially less than 380 mg, potentially less than 200mg, less than 100 mg, and even as low as 10 mg. These small quantitiesof both reactant and desiccant lend itself to a smaller form factor. Thesmall quantities also allow only a small volume of developer solution tobe dispensed for each test. As an example, for roughly 400 mg and silicaand 5-6 granules of calcium chloride, a sodium nitroprusside solutionwould only need to be combined in quantities of 40 to 50 microliters inorder to complete the reaction.

The cartridge reactant would be packed into a disk shape that resides ontop of the desiccant. In another embodiment, the cartridge reactant canbe loosely packed into the test chamber. The reactant would only useabout 50% of the normal volume. This loose packing of the reactant bedprovides less restriction of air flow, making the test chamber easier tobreathe through for the user. This reactant would be facing upward anddirectly contact the developer solution.

The base unit comprises a liquid delivery system that dispenses aprecise amount of liquid solution atop the cartridge, for example, the7-day cartridge. In one example, the delivery system applies lateralenergy to a plastic dropper that generates a precise “bead” of liquidwhen the energy is applied. The head of the dropper is immediately atopthe cartridge so that the drop immediately wicks through the layers ofthe cartridge. Once the solution has been dispensed and the chemicalreaction has been initiated, the sensor within the base unit would viewthe top of the reactant from an aerial perspective in order to measurethe response.

The breath analysis system shown in FIG. 65A is designed to separatebreath sample capture from breath sample analysis.

The separation of the capture of the breath sample from the analysis ofthe breath sample is achieved by the integrated mouthpiece. Eachcartridge test chamber is comprised of chemistry that allows the sampleto be collected separately from the base unit. The chemistry within thetest chamber is such that it can hold the absorbed analyte for aprolonged period of time. The cartridge could, as an example, recordmultiple samples over the course of the day, and maintain the sampleuntil the end of the day, when it is connected to the base unit andanalysis is performed. Table 5, below, highlights the time sequence forobtaining a response in a de-coupled system. Even when the actual baseunit coupling is delayed by two hours, the response is still generated,and the total test time from the perspective of the user is 60 seconds.

TABLE 5 Time (t = #:##:##: h:m:s) Step t = 0:00:00 to t = 0:00:10Deliver breath sample to cartridge t = 0:00:10 to t = 2:00:10 Usertravels with the cartridge only (e.g., at a gym, on a hike, at school,etc.) Analyte is absorbed into the cartridge reactant and remains intactt = 2:00:10 Insert cartridge into base unit t = 2:01:00 Receive baseunit response

Additionally, the separation of the sampling and analysis process isachieved by separation of the analyte chemistry. In this embodiment, thebase unit is comprised of a developer solution container. The developersolution within the container is meant to react with the reactant withinthe cartridge. When the cartridge is inserted into the base unit and atest chamber is aligned with the container, developer solution isdispensed onto the test chamber. This solution is meant to react withthe analyte that has been absorbed and captured in the cartridgechemistry. An example of this embodiment could be functionalized silicagel that readily absorbs acetone in the breath. The developer solutionwould be a liquid nitroprusside that, when in contact with the silicagel, reacts with the captured acetone and produces a color response.

In designs in which sample capture is separated from sample analysis,the time that the sample was captured is preferably documented. Theidentification of a specific test chamber relies on the relationshipbetween the cartridge and the integrated mouthpiece. The cartridge iscomprised of a ROM chip, which serves the purpose of storinginformation. This information can be stamped onto the chip, and can alsobe read off of the chip. The integrated mouthpiece is comprised of aclock mechanism that, when aligned with a cartridge, stamps informationonto its respective ROM chip. This information can include: testchamber, type of analyte within chamber, date and time of samplecollected within chamber, etc. Once the cartridge is inserted into thebase unit, the unit comprises a ROM chip reader that will read theinformation stored within the cartridge's chip. This information will beassociated with a test result at the end of analysis. Once a test iscomplete, all information will be provided to the user via the mobiledevice application. This information can also help determine whether ornot certain base unit components are required for that specific test. Asan example, if the test chamber chemistry is for a particular analytethat does not require a developer solution, the detachable liquidcontainer may not be utilized for that specific test.

Example of Breath Analysis Device Used to Monitor Success of KetogenicDiet

This particular system embodiment can be applicable to individualssuffering from epilepsy, specifically children. Ketogenic diets havebeen proven to reduce seizures in certain forms of epilepsy. For thisuse case, if test results need to be continuous, but not in real-time,the integrated mouthpiece would stamp the ROM chip with each date andtime that a sample was collected throughout the day. The cartridge wouldbe inserted into the base unit at the end of the day, and the testresults generated monitored would be provided to an individual that isnot the patient, in this case a parent or nurse. The test results wouldprovide feedback regarding the efficacy of the ketogenic diet for thechild. This design would allow a child to simply take a “whistle” (theintegrated mouthpiece) and a cartridge to the classroom instead of amore expensive base unit.

If test results needed to be continuous and provided in real time, thecartridge serves as a carrier for the child in order to easily providebreath samples. The actual analysis could be done by a nurse or aide atschool throughout the day to ensure that the child does not requiremedication at that time.

Example of Breath Analysis Device Used to Monitor Efficacy ofExercise/Diet

This particular system embodiment can be applicable in the case ofathletes, and can be optimized to measure ammonia levels in the breath.In this example, the primary chemistry would be a functionalized silicagel that can absorb ammonia when passed through via breath sample. Thesilica would be accompanied by a desiccant, such as a sodium hydroxidecoated silica. The liquid within the developer solution container wouldnot need to react with this chemistry in order to produce a result. Theuser would provide samples before a work out, after a work, and at othercritical points within their day if applicable. Once the cartridge isinserted into the base unit, the ROM chip would indicate that thecartridge involved ammonia chemistry, prompting the base unit towithhold the developer solution from the test reaction.

In this embodiment, the base unit would comprise a processor thatassists in the transfer of information between the base unit and otherdevices. This processor would allow an interaction between the base unitand the user's mobile device using either Wi-Fi capability, tetheringcapability, or a network broadcasting capability. These threecapabilities work either separately or in certain combinations toproduce different user “modes”. These modes are utilized depending onthe use case that the user finds themselves in. As an example, thisembodiment could use the Wi-Fi capability and the tethering capabilityfor a basic home use mode. In the event the user is traveling, thebroadcasting capability could utilize a generated network to create atravel mode; this mode would be used to connect to the base unit and getdata onto the user's mobile device. The base unit would also be poweredvia USB charging. This USB charging port could also be utilized in aninternal mode, where troubleshooting personnel can access the device viaUSB and pull data that would not be accessibly to a general user.Lastly, the Wi-Fi capability can also be utilized in a customer supportmode, where data from the base unit is generated and sent to a customersupport specialist in the form of reports.

FIG. 69 shows screen shots of a mobile application that is configured to“coach” a user through the process of ketone monitoring. Thisapplication is integrated with diet journals, such as MyFitnessPal.Using this information, the App looks for patterns and provides a simpletip to help the user make behavioral changes. One example is: identifythe highest carbohydrate content in any one food that the user consumed.Suggest that the user stop consuming that food. A second example is:identify a food that the user consumed repeatedly over the past 3 daysthat contains a decent number of carbohydrates. Suggest that the userstop consuming that food. In some instances, the messages that areprovided may be directed to the user himself or herself. But in otherinstances, the messages may be provided to the user's parent or coach,such as in the case of a parent of an epileptic 3-year old.

FIG. 74 illustrates a breath capture device that implements some of theabove-mentioned features. In the illustrated embodiment, one or moresensors 3100 are positioned along an influent flow path between thebreath input port and the valve 3102 to measure one or more exhalationcharacteristics of the user. As explained below, these exhalationcharacteristics may, in some embodiments, be used to configure orpersonalize the device for the user. In one embodiment, the only sensor3100 that is provided is a flow rate sensor or a pressure sensor,although various other types of sensors (such as a temperature sensor, acarbon dioxide sensor, or another type of gas sensor) may additionallyor alternatively be provided. Although the sensor(s) 3100 are shownalong the influent conduit, upstream from the valve, they mayadditionally or alternatively be positioned downstream from the valve,such as along the venting conduit and/or the conduit leading to thecapture chamber 3106.

As illustrated in FIG. 74 , the device includes a controller 3104 thatcontrols the state of the valve 3102 during the exhalation process toeffectively select the portion of the breath sample to be routed intothe capture chamber 3106. The controller may, for example, be amicrocontroller or microprocessor that executes program code stored in anon-transitory memory 3110. (All of the functions described below inconnection with FIG. 74 may be performed under the control of thisprogram code.) The device also includes a wireless transceiver 3112,such as a Bluetooth or WIFI transceiver, that enables the breath capturedevice to communicate with a smartphone or other mobile device (notshown) of the user. In some cases the mobile device may execute a mobileapplication that enables the user to configure and otherwise control thebreath capture device.

As illustrated, the memory 3110 persistently stores valve control data3120 that is used by the controller to control the timing with which thevalve state is changed during the capture process. (The valve 3102 inthe illustrated embodiment is a 2-way valve that routes the incomingbreath either to a venting port or to the capture chamber, depending onthe valve's state.) The valve control data is preferably generated orselected programmatically based on one or more characteristics of theuser, so that the operation of the valve is customized for theparticular user. This advantageously enables the breath capture deviceto account for the above-described variations in the breathingcharacteristics of individuals.

The valve control data may take on various forms, and may depend uponthe type or types of sensors included in the device. The table belowillustrates specific examples.

Sensor(s) Valve control data Flow rate The valve control data specifiesthe volume threshold at which the valve should be activated duringexhalation to cause the remaining portion of the breath sample to berouted to the capture chamber. This volume threshold is approximatelyequal to the “dead space” volume for the particular user, and may bedetermined by, for example, measuring the user's total exhalation volumeand multiplying this value by a constant such as_. The volume thresholdmay alternatively be calculated based on other characteristics of theuser, such as height and weight. Pressure The valve control dataspecifies the amount of time after exhalation begins (as detected by thepressure sensor) before the valve is activated to cause the remainingportion of the breath sample to be routed to the capture chamber. Thistime threshold may be selected by measuring the user's total exhalationtime as the user exhales into the device or a separate breath profilingdevice, and by multiplying this time value by a constant such as_. NoneSame as for pressure, except that the user indicates the initiation ofexhalation using either a switch on the device or a user interfaceelement of the mobile application.

The valve control data 3120 may alternatively be in the form of a modeidentifier or user type identifier. For example, the breath capturedevice may support 3, 4 or 5 different modes (or user types), each ofwhich is associated with a different set of one more valve controlparameters for controlling the valve. In these embodiments, thecurrently selected mode (or user type) may either be recorded in thememory 3110, or it may be selected by the user via a dial, switch, touchscreen, or other interface of the breath capture device.

The valve control data 3120 may be generated by the breath capturedevice, by an external source, or by a combination thereof. Thefollowing are examples of how the valve control data 3120 may begenerated:

Breath Capture Device Implements Breath Profiling Mode

In this embodiment, the breath capture device can be placed by the userinto a breath profiling mode via, for example, the mobile application ora switch on the breath capture device. When the user exhales into thebreath input port while the device is in this mode, the device measuresone or more exhalation characteristics of the user (such as thosementioned in the table above), and the controller 3104 uses thisinformation to generate the valve control data. (Any past valve controldata may be overwritten.) During this profiling process, the valve statemay remain unchanged so that the entire breath sample is vented from thedevice. At the end of the profiling process, the breath capture devicemay automatically transition into capture mode, and the user may exhaleinto the device a second time to enable the device to capture analveolar or other desired breath sample using the newly-generated valvecontrol data 3120. In some embodiments, the breath capture device mayenter into the breath profiling mode automatically after being used tocapture a breath sample (or after some default time period followingcapture), in which case the user may be expected to perform theprofiling process before each new breath sample is captured.

Breath Capture Device Determines Breath Profile from Prior CaptureCycle(s)

In this embodiment, the breath capture device determines the user'sbreath profile (and generates the associated valve control data) basedon measurements taken during one or more breath capture cycles. Thevalve control data may thus be generated using the same process asdescribed in #1 above, but without the need to implement a separatebreath profiling mode. For example, if the breath capture deviceincludes a flow rate sensor, the controller 3104 may measure the totalexhalation volume the first time the device is used to capture a breathsample, and may use this measurement to generate valve control data inthe form of a volume threshold. The next time the device is used tocapture a breath sample, this valve control data will be used to controlthe timing with which the valve state is changed. With each capturecycle thereafter, the device may use valve control data that is based onthe immediately preceding N breath capture cycles, where N may, forexample, be 1, 2, 3, 4, or 5 (optionally with more weight given to themost recent measurements); for example, if the user has used the deviceto capture 3 breath samples, a weighted average of the three associatedtotal exhalation volume measurements may be used to determine the volumethreshold for controlling the valve during the next capture cycle.

Use of Separate Breath Profiling Device

In some embodiments, the user may be asked to exhale into a separatebreath profiling device that measures one or more exhalationcharacteristics of the user as described above. This breath profilingdevice may then wirelessly communicate the measurement(s), or valvecontrol data derived therefrom, to the breath capture device.

Configuration Via Mobile Application (“App”)

In some embodiments, the user may configure the breath capture deviceusing the mobile application. For example, the mobile application mayprompt the user to enter one or more items of user data such as weight,height, gender, and age. The mobile application may then use thisinformation to generate the valve control data using one or more look uptables that map specific user attributes (such as weight and height) tospecific breathing characteristics such as lung capacity, and maywirelessly communicate this valve control data to the breath capturedevice. Alternatively, the mobile application may convey the userinformation to the breath capture device, which would then use thisinformation to generate the valve control data.

Hybrids of the Above

Any two or more of the four methods described above may be used incombination. As one example, the user may initially use a mobileapplication to configure/personalize the breath capture device as in #4above. Thereafter, the device may use method 1 and/or method 2 toautomatically adjust the valve control data over time.

Referring again to FIG. 74 , the capture chamber 3106 may, in someembodiments, be a reaction chamber that contains a reactant (typicallyin the form of reactive beads) that reacts to the breath sample. In suchembodiments, the breath capture device may also include a color sensor(not shown) for sensing a resulting color change representing an acetoneor other ketone concentration in the captured breath sample. In theseembodiments in which the breath capture device is also a breath analysisdevice, the controller 3104 may record each ketone measurement in thememory 3110 with associated metadata 3122 descriptive of the breathcapture cycle. Depending upon the type(s) of sensors 3100 (if any)provided, this metadata may include, for example, total exhalationvolume, average flow rate, maximum flow rate, exhalation time, pressure,exhalation volume prior to valve actuation, exhalation volume followingvalve actuation, valve actuation time relative to start of exhalation,time of day, etc. As explained above, these any other types ofmeasurement metadata may be useful for a variety of purposes, such asexplaining aberrational ketone measurements and improving the operationof the device.

During the breath capture process, the controller 3104 may, in someembodiments, determine whether the user's exhalation satisfies one ormore requirements, and may notify the user when it does not (e.g., viaan audible tone or by causing the mobile application to display an errormessage). The exhalation requirements may, in some cases, be based onone or more measurements taken during the above-described breathprofiling process. For example, during capture, the controller maycompare one or more exhalation characteristics (such as total exhalationtime, total exhalation volume, maximum flow rate, maximum pressure,etc.) to like measurements taken during the profiling process. If thecomparison yields a significant difference (e.g., a difference in timeor volume exceeding 20%), the controller may generate an error message.

Accounting for Valve Actuation Times

As explained above, the valve actuation time can be significant,especially if a gear-based linear actuator is used. To account for thevalve actuation time, the controller 3104 may be programmed topredictively or preemptively generate the signal for actuating the valve3102. For example, if the desired time threshold for actuating the valveis four seconds after exhalation begins, and the valve takes two secondsto change state, the controller may send a valve actuation signal twoseconds after exhalation begins. This may be accomplished either byusing valve control data that accounts for the valve actuation time, orby accounting for the delay via the executable program code 3108. Wherethe device uses flow volume to actuate the valve, the controller may usethe flow rate to determine how far in advance to actuate the valve suchthat the valve state will change at the desired volume threshold.

The description herein has largely been explained with respect to apatent or subject, terms used herein according to their common meaningsand used largely interchangeably. The description also has been focusedon application to human subjects, but this is not necessarily limiting.The principles of the invention also may be applied in veterinaryapplications.

It will be appreciated that the invention is not limited to the specificembodiments and method implementations described herein. The descriptionherein has largely been explained with respect to human patients orsubjects, but this is not necessarily limiting. The principles of theinvention also may be applied in veterinary applications.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than or equal to 10% of, within less than or equal to 5% of, withinless than or equal to 1% of, within less than or equal to 0.1% of, andwithin less than or equal to 0.01% of the stated amount. If the statedamount is 0 (e.g., none, having no), the above recited ranges can bespecific ranges, and not within a particular % of the value.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the claims that follow.

Similarly, this method of disclosure, is not to be interpreted asreflecting an intention that any claim require more features than areexpressly recited in that claim. Rather, as the following claimsreflect, inventive aspects lie in a combination of fewer than allfeatures of any single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment.

What is claimed is:
 1. A handheld breath analysis device, comprising: abreath input port having a mouthpiece that enables a user to exhale abreath sample into the breath analysis device; an analyte sensor capableof measuring a concentration of an analyte in breath; a valve fluidlycoupled to the breath input port, the valve switchable between a firstposition in which breath exhaled into the breath input port is ventedfrom the breath analysis device without exposure to the analyte sensor,and a second position in which breath exhaled into the breath input portis routed to the analyte sensor; a pressure sensor configured to detectan initiation of exhalation into the breath input port; and a controllerconfigured to control the valve during exhalation to cause a firstportion of the exhaled breath sample to be vented from the breathanalysis device and to cause a second portion of the exhaled breathsample to be routed to the analyte sensor, the controller configured tocontrol a timing with which the valve is switched from the firstposition to the second position based at least partly on (1) ameasurement of an amount of time that has transpired since initiation ofexhalation is detected using the pressure sensor, and (2) data regardingat least one characteristic of the user.
 2. The handheld breath analysisdevice of claim 1, further comprising a temperature sensor positionedalong an influent flow path between the breath input port and the valve,the temperature sensor connected to the controller.
 3. The handheldbreath analysis device of claim 1, further comprising a gas sensorpositioned along an influent flow path between the breath input port andthe valve, the gas sensor connected to the controller and configured tomeasure a particular type of gas in exhaled breath samples.
 4. Thehandheld breath analysis device of claim 1, wherein the analyte sensorcomprises: a cartridge into which the second portion of the exhaledbreath sample is routed; a light emitting diode that is positioned toilluminate the reaction chamber of the cartridge through a transparentwindow of the cartridge; and a photodiode positioned to measure lightfrom the light emitting diode that is reflected from the reactionchamber.
 5. The handheld breath analysis device of claim 1, furthercomprising a wireless transceiver, wherein the handheld breath analysisdevice is configured to communicate with a smartphone using the wirelesstransceiver.
 6. The handheld breath analysis device of claim 1, furthercomprising a status indicator that notifies a user of the device thatinitiation of exhalation is detected.
 7. The handheld breath analysisdevice of claim 1, wherein the analyte sensor is a nanoparticle sensor.8. The handheld breath analysis device of claim 1, further comprising adesiccant capable of removing moisture from the breath sample.
 9. Thehandheld breath analysis device of claim 8, wherein the desiccant is inthe mouthpiece.
 10. The handheld breath analysis device of claim 1,wherein the valve comprises a piston that slides in a proximal directionwithin a conduit of the breath analysis device in response toexhalation.
 11. The handheld breath analysis device of claim 1, furthercomprising a memory that stores valve control data, wherein thecontroller is configured to use the valve control data, in combinationwith the measurement of the amount of time that has transpired, todetermine when to switch the valve from the first position to the secondposition.
 12. The handheld breath analysis device of claim 11, whereinthe valve control data comprises data generated based on at least onemeasured breathing characteristic of the user.
 13. The handheld breathanalysis device of claim 1, wherein the controller is configured to usethe measurement of the amount of time that has transpired, incombination with exhalation flow rate data associated with the user, todetermine how much volume of breath has been exhaled by the user.
 14. Amethod performed by a controller of a handheld breath analysis device,the breath analysis device comprising a breath input port having amouthpiece that enables a user to exhale a breath sample into the breathanalysis device, an analyte sensor capable of measuring a concentrationof an analyte in breath, a valve fluidly coupled to the breath inputport, the valve switchable between a first position in which breathexhaled into the breath input port is vented from the breath analysisdevice without exposure to the analyte sensor and a second position inwhich breath exhaled into the breath input port is routed to the analytesensor, and a pressure sensor configured to detect an initiation ofexhalation into the breath input port, the method comprising: detecting,based on an output of the pressure sensor, initiation of exhalation by auser of a breath sample into the mouthpiece; during said exhalation,measuring, with a timer, an amount of time that has transpired sinceinitiation of exhalation; and determining, based at least partly on saidamount of time measured by the timer and data regarding at least onecharacteristic of the user, when to switch the valve from the firstposition to the second position.
 15. The method of claim 14, furthercomprising using valve control data stored in a memory of the handheldbreath analysis device, in combination with an output of the timer, todetermine when to switch the valve from the first position to the secondposition.
 16. The method of claim 15, wherein the valve control datacomprises data generated based on at least one measured breathingcharacteristic of the user.
 17. The method of claim 14, furthercomprising using an output of the timer, in combination with exhalationflow rate data associated with the user, to determine a volume of breathexhaled by the user.